The role of heat shock protein 70 (Hsp70) in radiation-induced immunomodulation

Human Gb3/CD77 synthase: a glycosyltransferase at the crossroads of immunohematology, toxicology, and cancer research

Human Gb3/CD77 synthase (α1,4-galactosyltransferase, P1/Pk synthase, UDP-galactose: β-D-galactosyl-β1-R 4-α-D-galactosyltransferase, EC 2.4.1.228) forms Galα1 → 4Gal structures on glycosphingolipids and glycoproteins. These glycans are recognized by bacterial adhesins and toxins. Globotriaosylceramide (Gb3), the major product of Gb3/CD77 synthase, is a glycosphingolipid located predominantly in plasma membrane lipid rafts, where it serves as a main receptor for Shiga toxins released by enterohemorrhagic Escherichia coli and Shigella dysenteriae of serotype 1. On the other hand, accumulation of glycans formed by Gb3/CD77 synthase contributes to the symptoms of Anderson-Fabry disease caused by α-galactosidase A deficiency. Moreover, variation in Gb3/CD77 synthase expression and activity underlies the P1PK histo-blood group system. Glycosphingolipids synthesized by the enzyme are overproduced in colorectal, gastric, pancreatic, and ovarian cancer, and elevated Gb3 biosynthesis is associated with cancer cell chemo- and radioresistance. Furthermore, Gb3/CD77 synthase acts as a key glycosyltransferase modulating ovarian cancer cell plasticity. Here, we describe the role of human Gb3/CD77 synthase and its products in the P1PK histo-blood group system, Anderson-Fabry disease, and bacterial infections. Additionally, we provide an overview of emerging evidence that Gb3/CD77 synthase and its glycosphingolipid products are involved in cancer metastasis and chemoresistance.

Radiofrequency radiation reshapes tumor immune microenvironment into antitumor phenotype in pulmonary metastatic melanoma by inducing active transformation of tumor-infiltrating CD8+ T and NK cells

Immunosuppression by the tumor microenvironment is a pivotal factor contributing to tumor progression and immunotherapy resistance. Priming the tumor immune microenvironment (TIME) has emerged as a promising strategy for improving the efficacy of cancer immunotherapy. In this study we investigated the effects of noninvasive radiofrequency radiation (RFR) exposure on tumor progression and TIME phenotype, as well as the antitumor potential of PD-1 blockage in a model of pulmonary metastatic melanoma (PMM). Mouse model of PMM was established by tail vein injection of B16F10 cells. From day 3 after injection, the mice were exposed to RFR at an average specific absorption rate of 9.7 W/kg for 1 h per day for 14 days. After RFR exposure, lung tissues were harvested and RNAs were extracted for transcriptome sequencing; PMM-infiltrating immune cells were isolated for single-cell RNA-seq analysis. We showed that RFR exposure significantly impeded PMM progression accompanied by remodeled TIME of PMM via altering the proportion and transcription profile of tumor-infiltrating immune cells. RFR exposure increased the activation and cytotoxicity signatures of tumor-infiltrating CD8+ T cells, particularly in the early activation subset with upregulated genes associated with T cell cytotoxicity. The PD-1 checkpoint pathway was upregulated by RFR exposure in CD8+ T cells. RFR exposure also augmented NK cell subsets with increased cytotoxic characteristics in PMM. RFR exposure enhanced the effector function of tumor-infiltrating CD8+ T cells and NK cells, evidenced by increased expression of cytotoxic molecules. RFR-induced inhibition of PMM growth was mediated by RFR-activated CD8+ T cells and NK cells. We conclude that noninvasive RFR exposure induces antitumor remodeling of the TIME, leading to inhibition of tumor progression, which provides a promising novel strategy for TIME priming and potential combination with cancer immunotherapy.

Carbon Ion Irradiation Activates Anti-Cancer Immunity

Carbon ion beams have the unique property of higher linear energy transfer, which causes clustered damage of DNA, impacting the cell repair system. This sometimes triggers apoptosis and the release in the cytoplasm of damaged DNA, leading to type I interferon (IFN) secretion via the activation of the cyclic GMP-AMP synthase-stimulator of interferon genes pathway. Dendritic cells phagocytize dead cancer cells and damaged DNA derived from injured cancer cells, which together activate dendritic cells to present cancer-derived antigens to antigen-specific T cells in the lymph nodes. Thus, carbon ion radiation therapy (CIRT) activates anti-cancer immunity. However, cancer is protected by the tumor microenvironment (TME), which consists of pro-cancerous immune cells, such as regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages. The TME is too robust to be destroyed by the CIRT-mediated anti-cancer immunity. Various modalities targeting regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages have been developed. Preclinical studies have shown that CIRT-mediated anti-cancer immunity exerts its effects in the presence of these modalities. In this review article, we provide an overview of CIRT-mediated anti-cancer immunity, with a particular focus on recently identified means of targeting the TME.

Radiation-targeted immunotherapy: A new perspective in cancer radiotherapy

In contemporary oncology, radiation therapy and immunotherapy stand as critical treatments, each with distinct mechanisms and outcomes. Radiation therapy, a key player in cancer management, targets cancer cells by damaging their DNA with ionizing radiation. Its effectiveness is heightened when used alongside other treatments like surgery and chemotherapy. Employing varied radiation types like X-rays, gamma rays, and proton beams, this approach aims to minimize damage to healthy tissue. However, it is not without risks, including potential damage to surrounding normal cells and side effects ranging from skin inflammation to serious long-term complications. Conversely, immunotherapy marks a revolutionary step in cancer treatment, leveraging the body's immune system to target and destroy cancer cells. It manipulates the immune system's specificity and memory, offering a versatile approach either alone or in combination with other treatments. Immunotherapy is known for its targeted action, long-lasting responses, and fewer side effects compared to traditional therapies. The interaction between radiation therapy and immunotherapy is intricate, with potential for both synergistic and antagonistic effects. Their combined use can be more effective than either treatment alone, but careful consideration of timing and sequence is essential. This review explores the impact of various radiation therapy regimens on immunotherapy, focusing on changes in the immune microenvironment, immune protein expression, and epigenetic factors, emphasizing the need for personalized treatment strategies and ongoing research to enhance the efficacy of these combined therapies in cancer care.

The radiation- and chemo-sensitizing capacity of diclofenac can be predicted by a decreased lactate metabolism and stress response

BACKGROUND

An enhanced aerobic glycolysis ("Warburg effect") associated with an increase in lactic acid in the tumor microenvironment contributes to tumor aggressiveness and resistance to radiation and chemotherapy. We investigated the radiation- and chemo-sensitizing effects of the nonsteroidal anti-inflammatory drug (NSAID) diclofenac in different cancer cell types.

METHODS

The effects of a non-lethal concentration of diclofenac was investigated on c-MYC and Lactate Dehydrogenase (LDH) protein expression/activity and the Heat shock Protein (HSP)/stress response in human colorectal (LS174T, LoVo), lung (A549), breast (MDA-MB-231) and pancreatic (COLO357) carcinoma cells. Radiation- and chemo-sensitization of diclofenac was determined using clonogenic cell survival assays and a murine xenograft tumor model.

RESULTS

A non-lethal concentration of diclofenac decreases c-MYC protein expression and LDH activity, reduces cytosolic Heat Shock Factor 1 (HSF1), Hsp70 and Hsp27 levels and membrane Hsp70 positivity in LS174T and LoVo colorectal cancer cells, but not in A549 lung carcinoma cells, MDA-MB-231 breast cancer cells and COLO357 pancreatic adenocarcinoma cells. The impaired lactate metabolism and stress response in diclofenac-sensitive colorectal cancer cells was associated with a significantly increased sensitivity to radiation and 5Fluorouracil in vitro, and in a human colorectal cancer xenograft mouse model diclofenac causes radiosensitization.

CONCLUSION

These findings suggest that a decrease in the LDH activity and/or stress response upon diclofenac treatment predicts its radiation/chemo-sensitizing capacity.

Engineering cancer cell membranes with endogenously upregulated HSP70 as a reinforced antigenic repertoire for the construction of material-free prophylactic cancer vaccines

Immune cells distinguish cancer cells mainly relying on their membrane-membrane communication. The major challenge of cancer vaccines exists in difficult identification of cancer neoantigens and poor understanding over immune recognition mechanisms against cancer cells, particularly the combination among multiple antigens and the cooperation between antigens and immune-associated proteins. We exploit cancer cell membranes as the whole cancer antigen repertoire and reinforce its immunogenicity by cellular engineering to modulate the cytomembrane's immune-associated functions. This study reports a vaccine platform based on radiation-engineered cancer cells, of which the membrane HSP70 protein as the immune chaperon/traitor is endogenously upregulated. The resulting positive influences are shown to cover immunogenic steps occurring in antigen-presenting cells, including the uptake and the cross-presentation of the cancer antigens, thus amplifying cancer-specific immunogenicity. Membrane vaccines offer chances to introduce desired metal ions through membrane-metal complexation. Using Mn2+ ion as the costimulatory interferon genes agonist, immune activity is enhanced to further boost adaptive cancer immunogenicity. Results have evidenced that this artificially engineered membrane vaccine with favorable bio-safety could considerably reduce tumorigenicity and inhibit tumor growth. This study provides a universally applicable and facilely available cancer vaccine platform by artificial engineering of cancer cells to inherit and amplify the natural merits of cancer cell membranes. STATEMENT OF SIGNIFICANCE: The major challenge of cancer vaccines exists in difficult identification of cancer neoantigens and poor understanding over immune recognition mechanisms against cancer cells, particularly the combination among multiple antigens and the cooperation between antigens and immune-associated proteins. Cancer cell membrane presents superior advantages as the whole cancer antigen repertoire, including the reported and the unidentified antigens, but its immunogenicity is far from satisfactory. Cellular engineering approaches offer chances to endogenously modulate the immune-associated functions of cell membranes. Such a reinforced vaccine based on the engineered cancer cell membranes matches better the natural immune recognition pathway than the conventional vaccines.

Extracellular heat shock protein 70 levels in tumour-bearing dogs and cats treated with radiation therapy and hyperthermia

Hyperthermia is a form of a cancer treatment which is frequently applied in combination with radiotherapy (RT) to improve therapy responses and radiosensitivity. The mode of action of hyperthermia is multifactorial; the one hand by altering the amount of the blood circulation in the treated tissue, on the other hand by modulating molecular pathways involved in cell survival processes and immunogenic interactions. One of the most dominant proteins induced by hyperthermia is the major stress-inducible heat shock protein 70 (Hsp70). Hsp70 can be found in the blood either as a free-protein (free HSP70) derived from necrotic cells, or lipid-bound (liposomal Hsp70) when it is actively released in extracellular vesicles (EVs) by living cells. The aim of the study was to evaluate the levels of free and liposomal Hsp70 before and after treatment with RT alone or hyperthermia combined with radiotherapy (HTRT) in dogs and cats to evaluate therapy responses. Peripheral blood was collected from feline and canine patients before and at 2, 4, 6 and 24 h after treatment with RT or HTRT. Hsp70 enzyme-linked immunosorbent assays (ELISAs) were performed to determine the free and liposomal Hsp70 concentrations in the serum. The levels were analysed after the first fraction of radiation to study immediate effects and after all applied fractions to study cumulative effects. The levels of free and liposomal Hsp70 levels in the circulation were not affected by the first singular treatment and cumulative effects of RT in cats however, after finalizing all treatment cycles with HTRT free and liposomal Hsp70 levels significantly increased. In dogs, HTRT, but not treatment with RT alone, significantly affected liposomal Hsp70 levels during the first fraction. Free Hsp70 levels were significantly increased after RT, but not HTRT, during the first fraction in dogs. In dogs, on the other hand, RT alone resulted in a significant increase in liposomal Hsp70, but HTRT did not significantly affect the liposomal Hsp70 when cumulative effects were analysed. Free Hsp70 was significantly induced in dogs after both, RT and HTRT when cumulative effects were analysed. RT and HTRT treatments differentially affect the levels of free and liposomal Hsp70 in dogs and cats. Both forms of Hsp70 could potentially be further investigated as potential liquid biopsy markers to study responses to RT and HTRT treatment in companion animals.

Heat Shock Factor 1 Inhibition: A Novel Anti-Cancer Strategy with Promise for Precision Oncology

Heat shock factor 1 (HSF1) is a transcription factor crucial for regulating heat shock response (HSR), one of the significant cellular protective mechanisms. When cells are exposed to proteotoxic stress, HSF1 induces the expression of heat shock proteins (HSPs) to act as chaperones, correcting the protein-folding process and maintaining proteostasis. In addition to its role in HSR, HSF1 is overexpressed in multiple cancer cells, where its activation promotes malignancy and leads to poor prognosis. The mechanisms of HSF1-induced tumorigenesis are complex and involve diverse signaling pathways, dependent on cancer type. With its important roles in tumorigenesis and tumor progression, targeting HSF1 offers a novel cancer treatment strategy. In this article, we examine the basic function of HSF1 and its regulatory mechanisms, focus on the mechanisms involved in HSF1's roles in different cancer types, and examine current HSF1 inhibitors as novel therapeutics to treat cancers.

Hsp70-Targeting and Size-Tunable Nanoparticles Combine with PD-1 Checkpoint Blockade to Treat Glioma

Invasive glioma usually disrupts the integrity of the blood-brain barrier (BBB), making the delivery of nanodrugs across the BBB possible, but sufficient targeting ability is still avidly needed to improve drug accumulation in glioma. Membrane-bound heat shock protein 70 (Hsp70) is expressed on the membrane of glioma cells rather than adjacent normal cells, therefore it can serve as a specific glioma target. Meanwhile, prolonging the retention in tumors is important for active-targeting nanoparticles to overcome receptor-binding barriers. Herein, the Hsp70-targeting and acid-triggered self-assembled gold nanoparticles (D-A-DA/TPP) are proposed to realize selective delivery of doxorubicin (DOX) to glioma. In the weakly acidic glioma matrix, D-A-DA/TPP formed aggregates to prolong retention, improve receptor-binding efficiency and facilitate acid-responsive DOX release. DOX accumulation in glioma induced immunogenic cell death (ICD) to promote antigen presentation. Meanwhile, combination with the PD-1 checkpoint blockade further activate T cells and provokes robust anti-tumor immunity. The results showed that D-A-DA/TPP can induce more glioma apoptosis. Furthermore, in vivo studies indicated D-A-DA/TPP plus PD-1 checkpoint blockade significantly improved median survival time. This study offeres a potential nanocarrier combining size-tunable strategy with active targeting ability to increase drug enrichment in glioma and synergizes with PD-1 checkpoint blockade to achieve chemo-immunotherapy.

Eco-friendly postharvest irradiation strategy with 131I isotope for environmental management of populations of migratory locust, Locusta migratoria

PURPOSE

Irradiation of food is promising for control of pests to minimize postharvest losses of yields and thus improvement of food safety, shelf life of produce. It is a method of choice that induces a series of lethal biochemical and molecular changes culminating into the engagement of a downstream cascade to cause abnormalities in irradiated pests. In this study, the effects of iodine-131 (131I) isotope radiation on the male gonad development of the migratory locust, Locusta migratoria, were evaluated.

MATERIALS AND METHODS

Newly emerged adult male locusts, less than one-day-old, were divided into two groups, control and irradiated. Locusts in the control group (n = 20 insects) didn't drink irradiated water and were reared under normal environmental conditions for one week. Locusts in the irradiated group (n = 20 insects) were exposed to irradiated water at a dose of 30 mCi and they were subsequently observed until they drank the whole quantity.

RESULTS

At the end of the experiment, scanning and electron microscopic examination of testes obtained from irradiated locusts revealed several major abnormalities, including malformed nuclei of spermatozoa, irregular plasma membranes, shrinkage of testicular follicles, vacuolated cytoplasm, disintegrated nebenkern and agglutinations of spermatids. Flow cytometry analysis revealed that 131I radiation induced both early and late apoptosis, but not necrosis, in testicular tissues. Testes of irradiated insects also exhibited a burst in reactive oxygen species (ROS), as indicated by significant elevation in amounts of malondialdehyde (MDA), a marker for peroxidation of lipids. In contrast, irradiation coincided with significant reductions in activities of enzymatic antioxidant biomarkers. Relative to controls, a three-fold upregulation of expression of mRNA of heat shock protein, Hsp90, was observed in testicular tissue of irradiated locusts. 131I-irradiated insects exhibited genotoxicity, as indicated by significant increases in various indicators of DNA damage by the comet assay, including tail length (7.80 ± 0.80 µm; p < .01), olive tail moment (40.37 ± 8.08; p < .01) and tail DNA intensity % (5.1 ± 0.51; p < .01), in testicular cells compared to the controls.

CONCLUSION

This is the first report on elucidation of I131-irradiation-mediated histopathological, biochemical and molecular mechanisms in gonads of male L. migratoria. Herein, the findings underscore the utility of 131I radiation as an eco-friendly postharvest strategy for management of insect pests and in particular for control of populations of L. migratoria.

Harnessing the Immunological Effects of Radiation to Improve Immunotherapies in Cancer

Ionizing radiation (IR) is used to treat 50% of cancers. While the cytotoxic effects related to DNA damage with IR have been known since the early 20th century, the role of the immune system in the treatment response is still yet to be fully determined. IR can induce immunogenic cell death (ICD), which activates innate and adaptive immunity against the cancer. It has also been widely reported that an intact immune system is essential to IR efficacy. However, this response is typically transient, and wound healing processes also become upregulated, dampening early immunological efforts to overcome the disease. This immune suppression involves many complex cellular and molecular mechanisms that ultimately result in the generation of radioresistance in many cases. Understanding the mechanisms behind these responses is challenging as the effects are extensive and often occur simultaneously within the tumor. Here, we describe the effects of IR on the immune landscape of tumors. ICD, along with myeloid and lymphoid responses to IR, are discussed, with the hope of shedding light on the complex immune stimulatory and immunosuppressive responses involved with this cornerstone cancer treatment. Leveraging these immunological effects can provide a platform for improving immunotherapy efficacy in the future.

Elevated Levels of Circulating Hsp70 and an Increased Prevalence of CD94+/CD69+ NK Cells Is Predictive for Advanced Stage Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the second most frequently diagnosed tumor worldwide. Despite the clinical progress which has been achieved by multimodal therapies, including radiochemotherapy, and immune checkpoint inhibitor blockade, the overall survival of patients with advanced-stage NSCLC remains poor, with less than 16 months. It is well established that many aggressive tumor entities, including NSCLC, overexpress the major stress-inducible heat shock protein 70 (Hsp70) in the cytosol, present it on the plasma membrane in a tumor-specific manner, and release Hsp70 into circulation. Although high Hsp70 levels are associated with tumor aggressiveness and therapy resistance, membrane-bound Hsp70 can serve as a tumor-specific antigen for Hsp70-primed natural killer (NK) cells, expressing the C-type lectin receptor CD94, which is part of the activator receptor complex CD94/NKG2C. Therefore, we investigated circulating Hsp70 levels and changes in the composition of peripheral blood lymphocyte subsets as potential biomarkers for the advanced Union for International Cancer Control (UICC) stages in NSCLC. As expected, circulating Hsp70 levels were significantly higher in NSCLC patients compared to the healthy controls, as well as in patients with advanced UICC stages compared to those in UICC stage I. Smoking status did not influence the circulating Hsp70 levels significantly. Concomitantly, the proportions of CD4+ T helper cells were lower compared to the healthy controls and stage I tumor patients, whereas that of CD8+ cytotoxic T cells was progressively higher. The prevalence of CD3-/CD56+, CD3-/NKp30, CD3-/NKp46+, and CD3-/NKG2D+ NK cells was higher in stage IV/IIIB of the disease than in stage IIIA but were not statistically different from that in healthy individuals. However, the proportion of NK cells expressing CD94 and the activation/exhaustion marker CD69 significantly increased in higher tumor stages compared with stage I and the healthy controls. We speculate that although elevated circulating Hsp70 levels might promote the prevalence of CD94+ NK cells in patients with advanced-stage NSCLC, the cytolytic activity of these NK cells also failed to control tumor growth due to insufficient support by pro-inflammatory cytokines from CD4+ T helper cells. This hypothesis is supported by a comparative multiplex cytokine analysis of the blood in lung cancer patients with a low proportion of CD4+ T cells, a high proportion of NK cells, and high Hsp70 levels versus patients with a high proportion of CD4+ T cells exhibiting lower IL-2, IL-4, IL-6, IFN-γ, granzyme B levels.

Advances in the study of HSP70 inhibitors to enhance the sensitivity of tumor cells to radiotherapy

The 70 kDa heat shock protein (HSP70) is one of the most conserved proteins and a ubiquitous molecular chaperone that plays a role in the folding, remodeling, and degradation of various proteins to maintain proteostasis. It has been shown that HSP70 is abundantly expressed in cancer and enhances tumor resistance to radiotherapy by inhibiting multiple apoptotic pathways, such as interfering with the cellular senescence program, promoting angiogenesis, and supporting metastasis. Thus, HSP70 provides an effective target for enhancing the effects of radiation therapy in the clinical management of cancer patients. Inhibition of HSP70 enhances the radiation-induced tumor-killing effect and thus improves the efficacy of radiotherapy. This article reviews the sensitivity of Hsp70 and its related inhibitors to radiotherapy of tumor cells.

Radiation therapy enhances systemic antitumor efficacy in PD-L1 therapy regardless of sequence of radiation in murine osteosarcoma

Recent studies demonstrate that immune checkpoint blockade (ICB) increases the chances of the abscopal effect, an anti-tumor effect outside the radiation field in radiation therapy. However, the optimal sequence between radiation and ICB remains unclear. To investigate the impact of sequence of radiation in anti-PD-L1 antibody (P1) therapy on immune microenvironments and antitumor efficacies in local and abscopal tumors, metastatic LM8 osteosarcoma cells were inoculated into both legs of C3H mice. For irradiation, only one side leg was irradiated at 10 Gy. Then mice were divided into four groups: administrated anti-PD-L1 antibody three times (P1 monotherapy), receiving radiation 3 days prior to P1 therapy (P1+pre-Rad), and receiving concurrent radiation with P1 therapy (P1+conc-Rad). Thereafter, tumor immune microenvironment and tumor volume changes were analyzed in irradiated and unirradiated tumors. The P1+pre-Rad regimen increased the proportion of CD8+ programmed cell death 1 (PD-1)+ granzyme B (GzmB)+ reinvigorated T cells and decreased the proportion of CD8+ PD-1+ GzmB- exhausted T cells than P1+conc-Rad regimen in unirradiated tumors. Combination regimens suppressed tumor growth in irradiated tumors compared with that in P1 monotherapy. In both irradiated and unirradiated tumors, significant tumor growth suppression and prolonged overall survival were observed under both combination treatment regimens compared with P1 monotherapy. However, no distinct differences in unirradiated tumor volume and survival were observed between P1+pre-Rad and P1+conc-Rad groups. These results suggest that local irradiation is necessary to improve systemic treatment efficacy in P1 therapy regardless of sequence of local irradiation.

The Role of TNF-α and Its Target HSP-70 in Triggering Apoptosis in Normozoospermic and Non-Normozoospermic Samples

Objective: Semen analysis is performed as one of the screening tests for infertility, including motility, morphology, and concentration observation. We aimed to investigate the expression rates of tumor necrosis factor-α (TNF-α) and heat shock protein (HSP)-70 as two opposite affectors of apoptosis in men with normal semen parameters and abnormal parameters to find the possible effect of this pathway on sperm parameters. We also aimed to investigate the apoptotic markers (DNA fragmentation and Caspase-3 expression) to observe the correlation of this pathway with apoptosis. Materials and Methods: A total of 32 men who applied for infertility evaluation were included in the study. Semen analysis was performed according to WHO criteria. Liquefaction time, appearance, volume, pH, viscosity, sperm concentration, total motility rate, sperm motility, and percentage of spermatozoa with normal morphology were determined. TNF-α, HSP-70, and Caspase-3 immunolocalization were scored histologically. A sperm chromatin dispersion test was used to observe DNA fragmentation. Results: There was no significant difference in TNF-α protein expression rate (mild level). The HSP-70 expression rate was lower, especially in the head region of normo. Caspase-3 was higher totally in non-normo. DNA fragmentation levels were similar in both the groups. Conclusion: From TNF-α protein expression at the mild level in both the groups, it may be hypothesized that the apoptotic pathway might not be triggered by the extrinsic pathway. We found a negative correlation between HSP-70 and Caspase-3 expressions, providing further evidence that HSP-70 works as an inhibitor to apoptosis. This, particularly on specific points, made us think the communication might begin in the anterior chamber, then flow through the cell body to the tail. HSP-70 expression was lower in normo than in non-normo, indicating the possible role of HSP-70 as an answer to any type of stressor in non-normozoospermic patients. Correspondingly, it may be concluded that HSP has an antiapoptotic effect, causing inhibition in the elimination of abnormal sperm cells impairing sperm parameters.

A Low Membrane Hsp70 Expression in Tumor Cells With Impaired Lactate Metabolism Mediates Radiosensitization by NVP-AUY922

As overexpression and membrane localization of stress proteins together with high lactate levels promote radioresistance in tumor cells, we studied the effect of the Hsp90 inhibitor NVP-AUY922 on the cytosolic and membrane expression of heat shock proteins (HSPs) and radiosensitivity in murine melanoma (B16F10) and human colorectal (LS174T) wildtype (WT) and lactate dehydrogenases A/B double knockout (LDH^−/−) tumor cells. Double knockout for LDHA/B has been found to reduce cytosolic as well as membrane HSP levels, whereas treatment with NVP-AUY922 stimulates the synthesis of Hsp27 and Hsp70, but does not affect membrane Hsp70 expression. Despite NVP-AUY922-inducing elevated levels of cytosolic HSP, radiosensitivity was significantly increased in WT cells and even more pronounced in LDH^−/− cells. An impaired lipid metabolism in LDH^−/− cells reduces the Hsp70 membrane-anchoring sphingolipid globotriaosylceramide (Gb3) and thereby results in a decreased Hsp70 cell surface density on tumor cells. Our results demonstrate that the membrane Hsp70 density, but not cytosolic HSP levels determines the radiosensitizing effect of the Hsp90 inhibitor NVP-AUY922 in LDH^−/− cells.

In vivo evaluation of oxidized multiwalled-carbon nanotubes-mediated hyperthermia treatment for breast cancer

Breast cancer is one of the most common types of cancer that contribute to high mortality worldwide. Hyperthermia (HT) was introduced as one of the alternative treatments to treat breast cancer but has major drawback of damaging normal adjacent cells. This study explores the integration effect of multiwalled‑carbon nanotubes (MWCNTs) in combination with hyperthermia treatment for breast cancer therapy regimes. In this study, acid-functionalized MWCNTs (ox-MWCNTs) were prepared by acid washing methods using H₂SO₄/HNO₃ (98%/68%) with the ratio of 3:1 (ν/ν) and characterized by colloidal dispersibility test, FTIR, TGA, XRD, FESEM and EDX analysis. EMT6 tumor-bearing mice were treated with ox-MWCNTs in combination with local HT at 43 °C. The tumor progression was monitored and the influence of immune response was evaluated. Results from this study demonstrated that mice from ox-MWCNTs in combination with local HT treatment group experienced complete tumor eradication, accompanied by a significant increase in median survival of the mice. Histological and immunohistochemical analysis of tumor tissues revealed that tumor treated with combined treatment underwent cell necrosis and there was a significant reduction of proliferating cells when compared to the untreated tumor. This observation is also accompanied with an increase in Hsp70 expression in tumor treated with HT. Flow cytometry analysis of the draining lymph nodes showed an increase in dendritic cells infiltration and maturation in mice treated with combined treatment. In addition, a significant increase of tumor-infiltrated CD8⁺ and CD4⁺ T cells along with macrophages and natural killer cells was observed in tumor treated with combined treatment. Altogether, results presented in this study suggested the potential of ox-MWCNTs-mediated HT as an anticancer therapeutic agent, hence might be beneficial in the future of breast cancer treatment.

Trans-resveratrol alleviates hepatic and renal injury in γ-irradiated rats

Background

Although ionizing radiation (IR) has been of immense value to human life due to its involvement in several fields, it doesn’t eliminate that exposure to IR results in an array of biological consequences, including oxidative stress, inflammation, and death. Thus, this study aimed to explore the curative effect of trans-Resveratrol (t-Res) on hepatic and renal injury in a rat model exposed to single and fractionated doses of γ-rays.

Methods

Rats exposed to a single dose of IR (6 Gy, as an acute effect) or a fractionated dose of IR (2 Gy/time/3 days, day after day; to imitate a chronic impact) were treated with t-Res. Then, the radio-protective effect of t-Res was investigated via biochemical and histological estimations in the liver and kidney of rats in the different groups.

Results

The data displayed a significant amelioration in biochemical and histological indices in the liver and kidney of rats exposed to IR doses and treated with t-Res. Particularly, t-Res reduced the oxidative stress milieu through decreasing HIF-1α, ROS, and MDA levels associated with increased CAT activity and Nrf-2 gene expression. Also, t-Res improved the inflammatory status via a decrease in TNF-α, NF-κB, SOCS-3, and HSP-70 genes expression linked with elevations in SIRT-1 and P53 genes expression.

Conclusion

It could be concluded that t-Res had hepatoprotective and renoprotective effects against the deleterious consequences of γ-rays exposure due to its antioxidant and anti-inflammatory properties.

NK Cells Armed with Chimeric Antigen Receptors (CAR): Roadblocks to Successful Development

In recent years, cell-based immunotherapies have demonstrated promising results in the treatment of cancer. Chimeric antigen receptors (CARs) arm effector cells with a weapon for targeting tumor antigens, licensing engineered cells to recognize and kill cancer cells. The quality of the CAR-antigen interaction strongly depends on the selected tumor antigen and its expression density on cancer cells. CD19 CAR-engineered T cells approved by the Food and Drug Administration have been most frequently applied in the treatment of hematological malignancies. Clinical challenges in their application primarily include cytokine release syndrome, neurological symptoms, severe inflammatory responses, and/or other off-target effects most likely mediated by cytotoxic T cells. As a consequence, there remains a significant medical need for more potent technology platforms leveraging cell-based approaches with enhanced safety profiles. A promising population that has been advanced is the natural killer (NK) cell, which can also be engineered with CARs. NK cells which belong to the innate arm of the immune system recognize and kill virally infected cells as well as (stressed) cancer cells in a major histocompatibility complex I independent manner. NK cells play an important role in the host’s immune defense against cancer due to their specialized lytic mechanisms which include death receptor (i.e., Fas)/death receptor ligand (i.e., Fas ligand) and granzyme B/perforin-mediated apoptosis, and antibody-dependent cellular cytotoxicity, as well as their immunoregulatory potential via cytokine/chemokine release. To develop and implement a highly effective CAR NK cell-based therapy with low side effects, the following three principles which are specifically addressed in this review have to be considered: unique target selection, well-designed CAR, and optimized gene delivery.

Abscopal Effects in Metastatic Cancer: Is a Predictive Approach Possible to Improve Individual Outcomes?

Patients with metastatic cancers often require radiotherapy (RT) as a palliative therapy for cancer pain. RT can, however, also induce systemic antitumor effects outside of the irradiated field (abscopal effects) in various cancer entities. The occurrence of the abscopal effect is associated with a specific immunological activation in response to RT-induced cell death, which is mainly seen under concomitant immune checkpoint blockade. Even if the number of reported apscopal effects has increased since the introduction of immune checkpoint inhibition, its occurrence is still considered rare and unpredictable. The cases reported so far may nevertheless allow for identifying first biomarkers and clinical patterns. We here review biomarkers that may be helpful to predict the occurrence of abscopal effects and hence to optimize therapy for patients with metastatic cancers.

Effect of hyperthermia and proton beam radiation as a novel approach in chordoma cells death and its clinical implication to treat chordoma

PURPOSE

Chordoma is a locally aggressive tumor that most commonly affects the base of the skull/clivus, cervical, and sacral spine. Conventional radiotherapy (RT), cannot be safely increased further to improve disease control due to the risk of toxicity to the surrounding critical structures. Tumor-targeted hyperthermia (HT) combined with Proton Beam Radiation Therapy (PBRT) is known to act as a potent radiosensitizer in cancer control. In this study, we investigated whether PBRT efficacy for chordoma can be enhanced in combination with HT as a radiosensitizer.

MATERIAL AND METHODS

Human chordoma cell lines, U-CH2 and Mug-chor1 were treated in vitro with HT followed by PBRT with variable doses. The colony-forming assay was performed, and dose-response was characterized by linear-quadratic model fits. HSP-70 and Brachyury (TBXT) biomarkers for chordoma aggression levels were quantified by western blot analysis. Gene microarray analysis was performed by U133 Arrays. Pathway Analysis was also performed using IPA bioinformatic software.

RESULTS

Our findings in both U-CH₂ and Mug-Chor1 cell lines demonstrate that hyperthermia followed by PBRT has an enhanced cell killing effect when compared with PBRT-alone (p < .01). Western blot analysis showed HT decreased the expression of Brachyury protein (p < .05), which is considered a biomarker for chordoma tumor aggression. HT with PBRT also exhibited an RT-dose-dependent decrease of Brachyury expression (p < .05). We also observed enhanced HSP-70 expression due to HT, RT, and HT + RT combined in both cell lines. Interestingly, genomic data showed 344 genes expressed by the treatment of HT + RT compared to HT (68 genes) or RT (112 genes) as individual treatment. We also identified activation of death receptor and apoptotic pathway in HT + RT treated cells.

CONCLUSION

We found that Hyperthermia (HT) combined with Proton Beam Radiation (PBRT) could significantly increase chordoma cell death by activating the death receptor pathway and apoptosis which has the promise to treat metastatic chordoma.

Biological consequences of cancer radiotherapy in the context of oral squamous cell carcinoma

Approximately 50% of subjects with cancer have been treated with ionizing radiation (IR) either as a curative, adjuvant, neoadjuvant or as a palliative agent, at some point during the clinical course of their disease. IR kills cancer cells directly by injuring their DNA, and indirectly by inducing immunogenic cell killing mediated by cytotoxic T cells; but it can also induce harmful biological responses to non-irradiated neighbouring cells (bystander effect) and to more distant cells (abscopal effect) outside the primary tumour field of irradiation.Although IR can upregulate anti-tumour immune reactions, it can also promote an immunosuppressive tumour microenvironment. Consequently, radiotherapy by itself is seldom sufficient to generate an effective long lasting immune response that is capable to control growth of metastasis, recurrence of primary tumours and development of second primary cancers. Therefore, combining radiotherapy with the use of immunoadjuvants such as immune checkpoint inhibitors, can potentiate IR-mediated anti-tumour immune reactions, bringing about a synergic immunogenic cell killing effect.The purpose of this narrative review is to discuss some aspects of IR-induced biological responses, including factors that contributes to tumour radiosensitivity/radioresistance, immunogenic cell killing, and the abscopal effect.

Targeting Cancer Metabolism Breaks Radioresistance by Impairing the Stress Response

Simple Summary

Ionizing radiation is a major pillar in the therapy of solid tumors. However, normal tissue toxicities and radioresistance of tumor cells can limit the therapeutic success of radiotherapy. In this study, we investigated the coregulation of the cancer metabolism and the heat shock response with respect to radioresistance. Our results indicate that an inhibition of lactate dehydrogenase, either pharmacologically or by gene knockout of LDHA and LDHB, significantly increases the radiosensitivity in tumor cells by global impairing of the stress response. Therefore, inhibition of the lactate metabolism might provide a promising strategy in the future to improve the clinical outcome of patients with highly aggressive, therapy-resistant tumors.

Abstract

The heightened energetic demand increases lactate dehydrogenase (LDH) activity, the corresponding oncometabolite lactate, expression of heat shock proteins (HSPs) and thereby promotes therapy resistance in many malignant tumor cell types. Therefore, we assessed the coregulation of LDH and the heat shock response with respect to radiation resistance in different tumor cells (B16F10 murine melanoma and LS174T human colorectal adenocarcinoma). The inhibition of LDH activity by oxamate or GNE-140, glucose deprivation and LDHA/B double knockout (LDH^−/−) in B16F10 and LS174T cells significantly diminish tumor growth; ROS production and the cytosolic expression of different HSPs, including Hsp90, Hsp70 and Hsp27 concomitant with a reduction of heat shock factor 1 (HSF1)/pHSF1. An altered lipid metabolism mediated by a LDHA/B double knockout results in a decreased presence of the Hsp70-anchoring glycosphingolipid Gb3 on the cell surface of tumor cells, which, in turn, reduces the membrane Hsp70 density and increases the extracellular Hsp70 levels. Vice versa, elevated extracellular lactate/pyruvate concentrations increase the membrane Hsp70 expression in wildtype tumor cells. Functionally, an inhibition of LDH causes a generalized reduction of cytosolic and membrane-bound HSPs in tumor cells and significantly increases the radiosensitivity, which is associated with a G2/M arrest. We demonstrate that targeting of the lactate/pyruvate metabolism breaks the radioresistance by impairing the stress response.

Single-Cell Imaging of m6 A Modified RNA Using m6 A-Specific In Situ Hybridization Mediated Proximity Ligation Assay (m6 AISH-PLA)

N⁶ -methyladenosine (m⁶ A) modification-the most prevalent mammalian RNA internal modification-plays key regulatory roles in mRNA metabolism. Current approaches for m⁶ A modified RNA analysis limit at bulk-population level, resulting in a loss of spatiotemporal and cell-to-cell variability information. Here we proposed a m⁶ A-specific in situ hybridization mediated proximity ligation assay (m⁶ AISH-PLA) for cellular imaging of m⁶ A RNA, allowing to identify m⁶ A modification at specific location in RNAs and image m⁶ A RNA with single-cell and single-molecule resolution. Using m⁶ AISH-PLA, we investigated the m⁶ A level and subcellular location of HSP70 RNA103-m⁶ A in response to heat shock stress, and found an increased m⁶ A modified ratio and an increased distribution ratio in cytoplasm under heat shock. m⁶ AISH-PLA can serve in the study of m⁶ A RNA in single cells for deciphering epitranscriptomic mechanisms and assisting clinical diagnosis.

Effects of aerobic and resistance exercise training associated with carnosine precursor supplementation on maximal strength and V̇O2max in rats with heart failure

BACKGROUND

Combined exercise training (CET) has been associated with positive responses in the clinical status of patients with heart failure (HF). Other nonpharmacological tools, such as amino acid supplementation, may further enhance its adaptation. The aim was to test whether CET associated with supplementing carnosine precursors could present better responses in the functional capacity and biochemical variables of rats with HF.

METHODS

Twenty-one male Wistar rats were subjected to myocardial infarction and allocated to three groups: sedentary (SED, n = 7), CET supplemented with placebo (CETP, n = 7), and CET with HF supplemented with β-alanine and L-histidine (CETS, n = 7). The trained animals were submitted to a strength protocol three times per week. Aerobic training was conducted twice per week. The supplemented group received β-alanine and L-histidine orally (250 mg/kg per day).

RESULTS

Maximum oxygen uptake, running distance, time to exhaustion and maximum strength were higher in the CET-P group than that in the SED group and even higher in the CET-S group than that in the CET-P group (P < 0.01). CET-S showed lower oxidative stress and inflammation markers and higher heat shock protein 72 kDa content and mRNA expression for calcium transporters in the skeletal muscle compared to SED.

CONCLUSION

CET together with β-alanine and L-histidine supplementation in rats with HF can elicit adaptations in both maximum oxygen uptake, running distance, time to exhaustion, maximum strength, oxidative stress, inflammation and mRNA expression. Carnosine may influence beneficial adjustments in the cell stress response in the skeletal muscle and upregulate the mRNA expression of calcium transporters.

Therapeutic response differences between 2D and 3D tumor models of magnetic hyperthermia

Magnetic hyperthermia-based cancer therapy (MHCT) has surfaced as one of the promising techniques for inaccessible solid tumors. It involves generation of localized heat in the tumor tissues on application of an alternating magnetic field in the presence of magnetic nanoparticles (MNPs). Unfortunately, lack of precise temperature and adequate MNP distribution at the tumor site under in vivo conditions has limited its application in the biomedical field. Evaluation of in vitro tumor models is an alternative for in vivo models. However, generally used in vitro two-dimensional (2D) models cannot mimic all the characteristics of a patient's tumor and hence, fail to establish or address the experimental variables and concerns. Considering that three-dimensional (3D) models have emerged as the best possible state to replicate the in vivo conditions successfully in the laboratory for most cell types, it is possible to conduct MHCT studies with higher clinical relevance for the analysis of the selection of magnetic parameters, MNP distribution, heat dissipation, action and acquired thermotolerance in cancer cells. In this review, various forms of 3D cultures have been considered and the successful implication of MHCT on them has been summarized, which includes tumor spheroids, and cultures grown in scaffolds, cell culture inserts and microfluidic devices. This review aims to summarize the contrast between 2D and 3D in vitro tumor models for pre-clinical MHCT studies. Furthermore, we have collated and discussed the usefulness, suitability, pros and cons of these tumor models. Even though numerous cell culture models have been established, further investigations on the new pre-clinical models and selection of best fit model for successful MHCT applications are still necessary to confer a better understanding for researchers.

Exposure to 2.45 GHz Radiation Triggers Changes in HSP-70, Glucocorticoid Receptors and GFAP Biomarkers in Rat Brain

Brain tissue may be especially sensitive to electromagnetic phenomena provoking signs of neural stress in cerebral activity. Fifty-four adult female Sprague-Dawley rats underwent ELISA and immunohistochemistry testing of four relevant anatomical areas of the cerebrum to measure biomarkers indicating induction of heat shock protein 70 (HSP-70), glucocorticoid receptors (GCR) or glial fibrillary acidic protein (GFAP) after single or repeated exposure to 2.45 GHz radiation in the experimental set-up. Neither radiation regime caused tissue heating, so thermal effects can be ruled out. A progressive decrease in GCR and HSP-70 was observed after acute or repeated irradiation in the somatosensory cortex, hypothalamus and hippocampus. In the limbic cortex; however, values for both biomarkers were significantly higher after repeated exposure to irradiation when compared to control animals. GFAP values in brain tissue after irradiation were not significantly different or were even lower than those of nonirradiated animals in all brain regions studied. Our results suggest that repeated exposure to 2.45 GHz elicited GCR/HSP-70 dysregulation in the brain, triggering a state of stress that could decrease tissue anti-inflammatory action without favoring glial proliferation and make the nervous system more vulnerable.

Immune profiles of male giant panda (Ailuropoda melanoleuca) during the breeding season

Background

The giant panda (Ailuropoda melanoleuca) is a threatened endemic Chinese species and a flagship species of national and global conservation concern. Life history theory proposes that reproduction and immunity can be mutually constraining and interrelated. Knowledge of immunity changes of male giant pandas during the breeding season is limited.

Results

Here, we researched peripheral blood gene expression profiles associated with immunity. Thirteen captive giant pandas, ranging from 9 to 11 years old, were divided into two groups based on their reproductive status. We identified 318 up-regulated DEGs and 43 down-regulated DEGs, which were enriched in 87 GO terms and 6 KEGG pathways. Additionally, we obtained 45 immune-related genes with altered expression, mostly up-regulated, and identified four hub genes HSPA4, SUGT1, SOD1, and IL1B in PPI analysis. These 45 genes were related to pattern recognition receptors, autophagy, peroxisome, proteasome, natural killer cell, antigen processing and presentation. SUGT1 and IL1B were related to pattern recognition receptors. HSP90AA1 was the most up-regulated gene and is a member of heat shock protein 90 family. HSP90 contributes to the translocation of extracellular antigen. KLRD1 encodes CD94, whose complex is an inhibitor of the cytotoxic activity of NK cells, was down-regulated. IGIP, which has the capability of inducing IgA production by B cells, was down-regulated, suggesting low concentration of IgA in male giant pandas. Our results suggest that most immune-related genes were up-regulated and more related to innate immune than adaptive immune.

Conclusions

Our results indicated that breeding male giant pandas presented an immunoenhancement in innate immunity, enhanced antigen presentation and processing in cellular immunity compared to non-breeding males. The humoral immunity of male giant pandas may show a tendency to decrease during the breeding season. This study will provide a foundation for further studies of immunity and reproduction in male giant pandas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07456-x.

Natural Killer Cells and Anti-Cancer Therapies: Reciprocal Effects on Immune Function and Therapeutic Response

Simple Summary

Natural Killer (NK) cells are innate lymphocytes that play an important role in the immune response against cancer. Their activity is controlled by a balance of inhibitory and activating receptors, which in cancer can be skewed to favor their suppression in support of immune escape. It is therefore imperative to find ways to optimize their antitumor functionality. In this review, we explore and discuss how their activity influences, or even mediates, the efficacy of various anti-cancer therapies and, vice versa, how their activity can be affected by these therapies. Knowledge of the mechanisms underlying these observations could provide rationales for combining anti-cancer treatments with strategies enhancing NK cell function in order to improve their therapeutic efficacy.

Abstract

Natural Killer (NK) cells are innate immune cells with the unique ability to recognize and kill virus-infected and cancer cells without prior immune sensitization. Due to their expression of the Fc receptor CD16, effector NK cells can kill tumor cells through antibody-dependent cytotoxicity, making them relevant players in antibody-based cancer therapies. The role of NK cells in other approved and experimental anti-cancer therapies is more elusive. Here, we review the possible role of NK cells in the efficacy of various anti-tumor therapies, including radiotherapy, chemotherapy, and immunotherapy, as well as the impact of these therapies on NK cell function.

Her2-Targeted Multifunctional Nano-Theranostic Platform Mediates Tumor Microenvironment Remodeling and Immune Activation for Breast Cancer Treatment

Purpose

The treatment of breast cancer is often ineffective due to the protection of the tumor microenvironment and the low immunogenicity of tumor cells, leading to a poor therapeutic effect. In this study, we designed a nano-theranostic platform for these obstacles: a photothermal effect mediated by a gold shell could remodel the tumor microenvironment by decreasing cancer-associated fibroblasts (CAFs) and promote the release of doxorubicin (DOX) from nanoparticles. In addition, it could realize photoacoustic (PA)/MRI dual-model imaging for diagnose breast cancer and targeted identification of Her2-positive breast cancer.

Methods

Her2-DOX-superparamagnetic iron oxide nanoparticles (SPIOs)@Poly (D, L-lactide-co-glycolide) acid (PLGA)@Au nanoparticles (Her2-DSG NPs) were prepared based on a single emulsion oil-in-water (O/W) solvent evaporation method, gold seed growing method, and carbon diimide method. The size distribution, morphology, PA/MRI imaging, drug loading capacity, and drug release were investigated. Cytotoxicity, antitumor effect, cellular uptake, immunogenic cell death (ICD) effect, and targeted performance on human Her2-positive BT474 cell line were investigated in vitro. BT474/Adr cells were constructed and the antitumor effect of NPs on it was evaluated in vitro. Moreover, chemical-photothermal therapy effect, PA/MRI dual-model imaging, ICD effect induced by NPs, and tumor microenvironment remodeling in human BT474 breast cancer nude mice model were also investigated.

Results

Nanoparticles were spherical, uniform in size and covered with a gold shell. NPs had a photothermal effect, and can realize photothermal-controlled drug release in vitro. Chemical-photothermal therapy had a good antitumor effect on BT474/Adr cells and on BT474 cells in vitro. The targeting evaluation in vitro showed that Her2-DSG NPs could actively target and identify Her2-positive tumor cells. The PA/MRI imaging was successfully validated in vitro/vivo. Similarly, NPs could enhance the ICD effect in vitro/vivo, which could activate an immune response. Immunofluorescence results also proved that photothermal effect could decrease CAFs to remodel the tumor microenvironment and enhance the accessibility of NPs to tumor cells. According to the toxicity results, targeted drug delivery combined with photothermal-responsive drug release proved that NPs had good biosafety in vivo. Chemical-photothermal therapy of Her2-targeted NPs has a good antitumor effect in the BT474 nude mice model.

Conclusion

Our study showed that chemical-photothermal therapy combined with tumor microenvironment remodeling and immune activation based on the Her2-DSG NPs we developed are very promising for Her2-positive breast cancer.

Organ-Specific Effects of Low Dose Radiation Exposure: A Comprehensive Review

Ionizing radiation (IR) is a high-energy radiation whose biological effects depend on the irradiation doses. Low-dose radiation (LDR) is delivered during medical diagnoses or by an exposure to radioactive elements and has been linked to the occurrence of chronic diseases, such as leukemia and cardiovascular diseases. Though epidemiological research is indispensable for predicting and dealing with LDR-induced abnormalities in individuals exposed to LDR, little is known about epidemiological markers of LDR exposure. Moreover, difference in the LDR-induced molecular events in each organ has been an obstacle to a thorough investigation of the LDR effects and a validation of the experimental results in in vivo models. In this review, we summarized the recent reports on LDR-induced risk of organ-specifically arranged the alterations for a comprehensive understanding of the biological effects of LDR. We suggested that LDR basically caused the accumulation of DNA damages, controlled systemic immune systems, induced oxidative damages on peripheral organs, and even benefited the viability in some organs. Furthermore, we concluded that understanding of organ-specific responses and the biological markers involved in the responses is needed to investigate the precise biological effects of LDR.

HSPA1L Enhances Cancer Stem Cell-Like Properties by Activating IGF1Rβ and Regulating β-Catenin Transcription

Studies have shown that cancer stem cells (CSCs) are involved in resistance and metastasis of cancer; thus, therapies targeting CSCs have been proposed. Here, we report that heat shock 70-kDa protein 1-like (HSPA1L) is partly involved in enhancing epithelial–mesenchymal transition (EMT) and CSC-like properties in non-small cell lung cancer (NSCLC) cells. Aldehyde dehydrogenase 1 (ALDH1) is considered a CSC marker in some lung cancers. Here, we analyzed transcriptional changes in genes between ALDH1high and ALDH1low cells sorted from A549 NSCLC cells and found that HSPA1L was highly expressed in ALDH1high cells. HSPA1L played two important roles in enhancing CSC-like properties. First, HSPA1L interacts directly with IGF1Rβ and integrin αV to form a triple complex that is involved in IGF1Rβ activation. HSPA1L/integrin αV complex-associated IGF1Rβ activation intensified the EMT-associated cancer stemness and γ-radiation resistance through its downstream AKT/NF-κB or AKT/GSK3β/β-catenin activation pathway. Secondly, HSPA1L was also present in the nucleus and could bind directly to the promoter region of β-catenin to function as a transcription activator of β-catenin, an important signaling protein characterizing CSCs by regulating ALDH1 expression. HSPA1L may be a novel potential target for cancer treatment because it both enhances IGF1Rβ activation and regulates γβ-catenin transcription, accumulating CSC-like properties.

Characterization of the Relationship between the Chaperone and Lipid-Binding Functions of the 70-kDa Heat-Shock Protein, HspA1A

HspA1A, a molecular chaperone, translocates to the plasma membrane (PM) of stressed and cancer cells. This translocation results in HspA1A’s cell-surface presentation, which renders tumors radiation insensitive. To specifically inhibit the lipid-driven HspA1A’s PM translocation and devise new therapeutics it is imperative to characterize the unknown HspA1A’s lipid-binding regions and determine the relationship between the chaperone and lipid-binding functions. To elucidate this relationship, we determined the effect of phosphatidylserine (PS)-binding on the secondary structure and chaperone functions of HspA1A. Circular dichroism revealed that binding to PS resulted in minimal modification on HspA1A’s secondary structure. Measuring the release of inorganic phosphate revealed that PS-binding had no effect on HspA1A’s ATPase activity. In contrast, PS-binding showed subtle but consistent increases in HspA1A’s refolding activities. Furthermore, using a Lysine-71-Alanine mutation (K71A; a null-ATPase mutant) of HspA1A we show that although K71A binds to PS with affinities similar to the wild-type (WT), the mutated protein associates with lipids three times faster and dissociates 300 times faster than the WT HspA1A. These observations suggest a two-step binding model including an initial interaction of HspA1A with lipids followed by a conformational change of the HspA1A-lipid complex, which accelerates the binding reaction. Together these findings strongly support the notion that the chaperone and lipid-binding activities of HspA1A are dependent but the regions mediating these functions do not overlap and provide the basis for future interventions to inhibit HspA1A’s PM-translocation in tumor cells, making them sensitive to radiation therapy.

Targets for protection and mitigation of radiation injury

Protection of normal tissues against toxic effects of ionizing radiation is a critical issue in clinical and environmental radiobiology. Investigations in recent decades have suggested potential targets that are involved in the protection against radiation-induced damages to normal tissues and can be proposed for mitigation of radiation injury. Emerging evidences have been shown to be in contrast to an old dogma in radiation biology; a major amount of reactive oxygen species (ROS) production and cell toxicity occur during some hours to years after exposure to ionizing radiation. This can be attributed to upregulation of inflammatory and fibrosis mediators, epigenetic changes and disruption of the normal metabolism of oxygen. In the current review, we explain the cellular and molecular changes following exposure of normal tissues to ionizing radiation. Furthermore, we review potential targets that can be proposed for protection and mitigation of radiation toxicity.

Role of HSP70 in response to (thermo)radiotherapy: analysis of gene expression in canine osteosarcoma cells by RNA-seq

Pre-treatment of tumors with hyperthermia is often used to increase the efficacy of radiotherapy. One of the main proteins induced in response to hyperthermia is heat shock protein 70 (HSP70). The aim of our study was to investigate up- and down-regulated genes in response to (thermo)radiotherapy in HSP70 proficient and deficient canine osteosarcoma cell line (Abrams), and functional role of HSP70 in the mechanism of thermoradiosensitization. Cells were transfected with negative control siRNA or siRNA targeting HSP70 and treated with hyperthermia (HT), radiotherapy (RT), and thermoradiotherapy (HTRT). RNA sequencing was used to analyze gene expression. Hyperthermia and thermoradiotherapy, but not radiotherapy alone, induced differential gene expression. We identified genes differentially expressed only in HSP70 knockdown (thus HSP70-dependent) cells in response to hyperthermia and thermoradiotherapy. Interestingly, cell proliferation but not clonogenicity and apoptosis/necrosis was affected by the HSP70 knockdown in response to thermoradiotherapy. The results suggest that HSP70 regulates expression of specific genes in response to hyperthermia and thermoradiotherapy. Further investigations into the role of specific genes regulated in a HSP70-dependent manner in response to thermoradiotherapy could pave a way into new, combinatorial treatment options for (canine) osteosarcoma and other cancer types.

Time- and Dose-Dependent Effects of Ionizing Irradiation on the Membrane Expression of Hsp70 on Glioma Cells

The major stress-inducible protein Hsp70 (HSPA1A) is overexpressed in the cytosol of many highly aggressive tumor cells including glioblastoma multiforme and presented on their plasma membrane. Depending on its intracellular or membrane localization, Hsp70 either promotes tumor growth or serves as a target for natural killer (NK) cells. The kinetics of the membrane Hsp70 (mHsp70) density on human glioma cells (U87) was studied after different irradiation doses to define the optimal therapeutic window for Hsp70-targeting NK cells. To maintain the cells in the exponential growth phase during a cultivation period of 7 days, different initial cell counts were seeded. Although cytosolic Hsp70 levels remained unchanged on days 4 and 7 after a sublethal irradiation with 2, 4 and 6 Gy, a dose of 2 Gy resulted in an upregulated mHsp70 density in U87 cells which peaked on day 4 and started to decline on day 7. Higher radiation doses (4 Gy, 6 Gy) resulted in an earlier and more rapid onset of the mHsp70 expression on days 2 and 1, respectively, followed by a decline on day 5. Membrane Hsp70 levels were higher on cells in G2/M than in G1; however, an irradiation-induced cell cycle arrest on days 4 and 7 was not associated with an increase in the mHsp70 density. Extracellular Hsp70 concentrations in the supernatant of irradiated cells were significantly higher than sham (0 Gy) irradiated cells on days 4 and 7, but not on day 1. Functionally, elevated mHsp70 densities were associated with a significantly better lysis by Hsp70-targeting NK cells. In summary, the kinetics of changes in the mHsp70 density upon irradiation on tumor cells is time- and dose-dependent.

Heat Shock Proteins: Agents of Cancer Development and Therapeutic Targets in Anti-Cancer Therapy

Heat shock proteins (HSPs) constitute a large family of molecular chaperones classified by their molecular weights, and they include HSP27, HSP40, HSP60, HSP70, and HSP90. HSPs function in diverse physiological and protective processes to assist in maintaining cellular homeostasis. In particular, HSPs participate in protein folding and maturation processes under diverse stressors such as heat shock, hypoxia, and degradation. Notably, HSPs also play essential roles across cancers as they are implicated in a variety of cancer-related activities such as cell proliferation, metastasis, and anti-cancer drug resistance. In this review, we comprehensively discuss the functions of HSPs in association with cancer initiation, progression, and metastasis and anti-cancer therapy resistance. Moreover, the potential utilization of HSPs to enhance the effects of chemo-, radio-, and immunotherapy is explored. Taken together, HSPs have multiple clinical usages as biomarkers for cancer diagnosis and prognosis as well as the potential therapeutic targets for anti-cancer treatment.

Macrophages reprogrammed by lung cancer microparticles promote tumor development via release of IL-1β

Despite their mutual antagonism, inflammation and immunosuppression coexist in tumor microenvironments due to tumor and immune cell interactions, but the underlying mechanism remains unclear. Previously, we showed that tumor cell-derived microparticles induce an M2 phenotype characterized by immunosuppression in tumor-infiltrating macrophages. Here, we further showed that lung cancer microparticles (L-MPs) induce macrophages to release a key proinflammatory cytokine, IL-1β, thus promoting lung cancer development. The underlying mechanism involves the activation of TLR3 and the NLRP3 inflammasome by L-MPs. More importantly, tyrosine kinase inhibitor treatment-induced L-MPs also induce human macrophages to release IL-1β, leading to a tumor-promoting effect in a humanized mouse model. These findings demonstrated that in addition to their anti-inflammatory effect, L-MPs induce a proinflammatory phenotype in tumor-infiltrating macrophages, promoting the development of inflammatory and immunosuppressive tumor microenvironments.

Accelerated, but not conventional, radiotherapy of murine B-cell lymphoma induces potent T cell-mediated remissions

Conventional local tumor irradiation (LTI), delivered in small daily doses over several weeks, is used clinically as a palliative, rather than curative, treatment for chemotherapy-resistant diffuse large B-cell lymphoma (DLBCL) for patients who are ineligible for hematopoietic cell transplantation. Our goal was to test the hypothesis that accelerated, but not conventional, LTI would be more curative by inducing T cell-mediated durable remissions. We irradiated subcutaneous A20 and BL3750 lymphoma tumors in mice with a clinically relevant total radiation dose of 30 Gy LTI, delivered in 10 doses of 3 Gy over 4 days (accelerated irradiation) or as 10 doses of 3 Gy over 12 days (conventional irradiation). Compared with conventional LTI, accelerated LTI resulted in more complete and durable tumor remissions. The majority of these mice were resistant to rechallenge with lymphoma cells, demonstrating the induction of memory antitumor immunity. The increased efficacy of accelerated LTI correlated with higher levels of tumor cell necrosis vs apoptosis and expression of "immunogenic cell death" markers, including calreticulin, heat shock protein 70 (Hsp70), and Hsp90. Accelerated LTI-induced remissions were not seen in immunodeficient Rag-2 ^-/- mice, CD8⁺ T-cell-depleted mice, or Batf-3 ^-/- mice lacking CD8α⁺ and CD103⁺ dendritic cells. Accelerated, but not conventional, LTI in immunocompetent hosts induced marked increases in tumor-infiltrating CD4⁺ and CD8⁺ T cells and MHCII⁺CD103⁺CD11c⁺ dendritic cells and corresponding reductions in exhausted PD-1⁺Eomes⁺CD8⁺ T cells and CD4⁺CD25⁺FOXP3⁺ regulatory T cells. These findings raise the possibility that accelerated LTI can provide effective immune control of human DLBCL.

Cell line-specific efficacy of thermoradiotherapy in human and canine cancer cells in vitro

Objective

Aims were to investigate sensitivity of various human and canine cancer cell lines to hyperthermia and the influence of particular treatment conditions, and to analyze the DNA-damage response and mode of cell death in cell line radiosensitized by hyperthermia. Additionally, we were interested in the involvement of HSP70 in radiosensitization.

Methods

Radiosensitization by hyperthermia was determined in a panel of human and canine cancer cell lines using clonogenic cell survival assay, as well as levels of heat shock proteins (HSPs) using immunoblotting. The influence of the hyperthermia-radiotherapy time gap, different temperatures and the order of treatments on clonogenicity of hyperthermia-sensitive A549 cells was investigated. Additionally, DNA damage and cell death were assessed by Comet assay and an apoptosis/necrosis assay. Further we induced transient knockdown in A549 cells to test HSP70’s involvement in radiosensitization.

Results

Out of eight cell lines tested, only two (A549 and Abrams) showed significant decrease in clonogenic cell survival when pre-treated with hyperthermia at 42°C. Strong induction of HSP70 upon thermoradiotherapy (HT-RT) treatment was found in all cell lines. Transient knockdown of HSP70 in A549 cells did not result in decrease of clonogenic cell survival in response to HT-RT.

Conclusion

Tumor cell-type, temperature and order of treatment play an important role in radiosensitization by hyperthermia. However, hyperthermia has limited potency to radiosensitize canine cancer cells grown in a 2D cell culture setting presented here. DNA damage and apoptosis/necrosis did not increase upon combined treatment and cytosolic levels of HSP70 appear not to play critical role in the radiosensitization of A549 cells.

Gut microbiota: implications for radiotherapy response and radiotherapy-induced mucositis

Radiotherapy is a mainstay of solid tumor management but can be associated with unacceptable levels of off-target tissue toxicity which impact treatment outcomes and patients' quality of life. Tumour response to radiotherapy and the frequency and severity of radiotherapy-induced toxicities, especially mucositis, varies among patients. Gut microbiota has been found to modulate both the efficacy and toxicity of some types of cancer chemotherapies and immunotherapies but has yet to be investigated thoroughly in the setting of radiotherapy. Area covered: In this review, we discuss the potential role of gut microbiota on modulating radiotherapy-induced oral and gastrointestinal mucositis and the anti-tumor response to radiotherapy through modulation of immune responses. Expert opinion: The gut microbiota plays a major role in the modulation of systemic immune responses, which influence both radiotherapy response and gastrointestinal toxicities such as mucositis. Hence, investigating the gut microbiota link to the variation in radiotherapy responses and toxicities among patients is warranted. Future targeting of these responses with a patient-tailored restoration of optimal microbial composition could lead to a new era of mucositis prevention and enhanced tumor responses.

Increased heat shock protein 70 expression attenuates pancreatic fibrosis induced by dibutyltin dichloride

OBJECTIVES

Heat shock protein (HSP) 70 performs a chaperoning function and protects cells against injury. Although the effect of HSPs against acute inflammatory change has been proven, the relationship between HSP70 and chronic pancreatitis remains unclear. This study aimed to investigate the protective effect of increased HSP70 expression induced by thermal stress against pancreatic fibrosis in experimental chronic pancreatitis.

MATERIALS AND METHODS

Two experiments to evaluate pancreatic HSP70 expression induced by thermal stress and determine the effect of increased HSP70 expression against pancreatic fibrosis were performed. To investigate HSP70 expression, rats were immersed in a warm bath and sequentially killed, and pancreatic HSP70 expression was measured. To study the effect of increased HSP70 expression, pancreatic fibrosis was induced by intravenous injection of dibutyltin dichloride (DBTC) and analyzed under repeated thermal stress. The severity of pancreatic fibrosis was measured.

RESULTS

Thermal stress significantly increased HSP70 expression in the pancreas. HSP70 expression peaked at 6-12 h after warm bathing, and the increased HSP70 expression was associated with the attenuation of pancreatic fibrosis. Although pancreatic fibrosis was induced by DBTC injection, HSP70 expression induced by repeated thermal stress diminished the severity of atrophy and fibrosis. On western blot analysis, collagen type 1 expression was diminished in the increased HSP70 expression group, but not α-smooth muscle actin expression.

CONCLUSIONS

Thermal stress could increase pancreatic HSP70 expression, and induced HSP70 expression showed a protective effect against pancreatic fibrosis. Modulation of HSP70 expression could be a potential therapeutic target in the treatment of chronic pancreatitis.

Nutrition and water temperature regulate the expression of heat-shock proteins in golden pompano larvae (Trachinotus ovata, Limmaeus 1758)

Understanding fish larval development is of a great interest for aquaculture production efficiency. Identifying possible indicators of fish larvae stress could improve the production and limit the mortality rate that larval stage is subjected to. Heat-shock proteins (HSPs) and heat-shock factors (HSFs) are well known as indicators of response to many kinds of stressor (e.g., environmental, morphological, or pathological changes). In this study, golden pompano larvae were raised at different temperatures (23 °C, 26 °C, and 29 °C), as well as three different diets (Artemia nauplii unenriched, Artemia nauplii enriched with Nannochloropsis sp., and Artemia nauplii enriched with Algamac 3080), and the expression of HSP60, HSP70, HSF1, HSP2, and GRP94 were monitored. While stress genes were widely expressed in the larval tissues, HSP60 and HSP70 were principally from the gills and heart; HSF1 principally from the muscle, brain, and heart; and GRP94 principally from the head kidney and spleen. Golden pompano larvae were found to be more sensitive to thermal changes at later larval stage, and 29 °C was showed to likely be the best condition for golden pompano larval development. Nannochloropsis sp.-enriched Artemia nauplii treatment was found to be the most appropriate feed type with moderate relative expressions of HSP60, HSP70, HSF1, HSF2, and GRP94.

High serum Hsp70 level predicts poor survival in colorectal cancer: Results obtained in an independent validation cohort

BACKGROUND

Hsp70 plays important role in the development and progression of cancer. Previously we described the association between serum Hsp70 levels and mortality of colorectal cancer.

OBJECTIVE

In this new prospective study we aimed to confirm and extend our previous findings in a larger cohort of patients, based on a longer follow-up period.

METHODS

Two hundred and thirty-two patients diagnosed with colorectal cancer were enrolled in the study. Baseline serum Hsp70 level and classical biomarker levels were measured. Patients were treated according to stage of the tumor and follow-up lasted for a median 46.4 months.

RESULTS

We found that serum Hsp70 concentrations increase significantly with stage of the disease (1.79; 2.23 and 3.21 ng/ml in stage I+II, III and IV respectively, p= 0.012 and 0.002, Mann-Whitney test) and with other known biomarkers of the disease. We managed to confirm our previous findings that high baseline serum Hsp70 level (> 1.64 ng/ml) predicted poor 5-year survival (risk of death HR: 1.94 CI: 1.294-2.909; univariate; HR: 2.418 CI: 1.373-4.258; multivariate Cox regression analysis) in the whole patient population and also in subgroups of stage IV and stage III disease. The strongest association was observed in women under age of 70 (HR: 8.12, CI: 2.02-35.84; p= 0.004; multivariate Cox regression). The power of this colorectal cancer prognostic model could be amplified by combining Hsp70 levels and inflammatory markers. Patients with high Hsp70, CRP and high baseline WBC or platelet count had 5-times higher risk of death (HR: 5.07 CI: 2.74-9.39, p< 0.0001; and HR: 4.98 CI: 3.08-8.06, p< 0.0001 respectively).

CONCLUSIONS

These results confirm and validate our previous findings that serum Hsp70 is a useful biomarker of colorectal cancer.

Novel Approaches to Improve the Efficacy of Immuno-Radiotherapy

Radiotherapy (RT) has been applied for decades as a treatment modality in the management of various types of cancer. Ionizing radiation induces tumor cell death, which in turn can either elicit protective anti-tumor immune responses or immunosuppression in the tumor micromilieu that contributes to local tumor recurrence. Immunosuppression is frequently accompanied by the attraction of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs), M2 tumor-associated macrophages (TAMs), T regulatory cells (Tregs), N2 neutrophils, and by the release of immunosuppressive cytokines (TGF-β, IL-10) and chemokines. Immune checkpoint pathways, particularly of the PD-1/PD-L1 axis, have been determined as key regulators of cancer immune escape. While IFN-dependent upregulation of PD-L1 has been extensively investigated, up-to-date studies indicated the importance of DNA damage signaling in the regulation of PD-L1 expression following RT. DNA damage dependent PD-L1 expression is upregulated by ATM/ATR/Chk1 kinase activities and cGAS/STING-dependent pathway, proving the role of DNA damage signaling in PD-L1 induced expression. Checkpoint blockade immunotherapies (i.e., application of anti-PD-1 and anti-PD-L1 antibodies) combined with RT were shown to significantly improve the objective response rates in therapy of various primary and metastatic malignancies. Further improvements in the therapeutic potential of RT are based on combinations of RT with other immunotherapeutic approaches including vaccines, cytokines and cytokine inducers, and an adoptive immune cell transfer (DCs, NK cells, T cells). In the current review we provide immunological rationale for a combination of RT with various immunotherapies as well as analysis of the emerging preclinical evidences for these therapies.

Flavonoids protect colon against radiation induced colitis

Radiation induced colitis is one the most common clinical issue for patients receiving radiotherapy. For this reason, we aimed to investigate the effect of antioxidant-effective flavonoids hesperidin and quercetin on the intestinal damage induced by radiation in this study. TNF-alpha, interleukin-10 (IL-10), heat shock protein 70 (HSP 70) and caspase 3, 8, 9 markers of apoptotic pathways were measured in the colon tissues of irradiated acute intestinal damage by enzyme-linked immunosorbent assay (ELISA). Irradiation of rats caused a significance increase of TNF-alpha, caspase 3/8/9 and decrease of IL-10 concentrations. Hesperidin and quercetin treatment resulted in decreased levels of TNF-alpha and increased levels of IL-10. Quercetin significantly decreased caspase 3/8/9 levels. Hesperidin produced a decreased of caspase 3/8/9 levels compared with irradiation group but this was statistically not significant. Only significant alteration of HSP 70 were seen in hesperidin treated rats. Further studies are needed to elucidate the mechanism by which flavonoids induced signaling provides protection against apoptosis and inflammation.

Granzyme B Functionalized Nanoparticles Targeting Membrane Hsp70-Positive Tumors for Multimodal Cancer Theranostics

Functionalized superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as potential clinical tools for cancer theranostics. Membrane-bound 70 kDa heat shock protein (mHsp70) is ubiquitously expressed on the cell membrane of various tumor types but not normal cells and therefore provides a tumor-specific target. The serine protease granzyme B (GrB) that is produced as an effector molecule by activated T and NK cells has been shown to specifically target mHsp70 on tumor cells. Following binding to Hsp70, GrB is rapidly internalized into tumor cells. Herein, it is demonstrated that GrB functionalized SPIONs act as a contrast enhancement agent for magnetic resonance imaging and induce specific tumor cell apoptosis. Combinatorial regimens employing stereotactic radiotherapy and/or magnetic targeting are found to further enhance the therapeutic efficacy of GrB-SPIONs in different tumor mouse models.