RESUMO
Objective: To investigate the effect of high-fat and low-carbohydrate diet combined with radiotherapy on the tumor microenvironment of mice with lung xenografts. Methods: C57BL/6J mice were selected to establish the Lewis lung cancer model, and they were divided into the normal diet group, the high-fat and low-carbohydrate diet group, the normal diet + radiotherapy group, and the high-fat and low-carbohydrate diet + radiotherapy group, with 18 mice in each group. The mice in the normal diet group and the normal diet + radiotherapy group were fed with the normal diet with 12.11% fat for energy supply, and the mice in the high-fat and low-carbohydrate diet group and the high-fat and low-carbohydrate diet + radiotherapy group were fed with high-fat and low-carbohydratediet with 45.00% fat for energy. On the 12th to 14th days, the tumor sites of the mice in the normal diet + radiotherapy group and the high-fat and low-carbohydrate diet + radiotherapy group were treated with radiotherapy, and the irradiation dose was 24 Gy/3f. The body weight, tumor volume, blood glucose and blood ketone level, liver and kidney function, and survival status of the mice were observed and monitored. Immunohistochemical staining was used to detect the tumor-associated microangiogenesis molecule (CD34) and lymphatic endothelial hyaluronan receptor 1 (LYVE-1), Sirius staining was used to detect collagen fibers, and multiplex immunofluorescence was used to detect CD8 and programmed death-1 (PD-1). Expression of immune cell phenotypes (CD3, CD4, CD8, and Treg) was detected by flow cytometry. Results: On the 27th day after inoculation, the body weigh of the common diet group was(24.78±2.22)g, which was significantly higher than that of the common diet + radiotherapy group [(22.15±0.48)g, P=0.030] and high-fat low-carbohydrate diet + radiotherapy group [(22.02±0.77)g, P=0.031)]. On the 15th day after inoculation, the tumor volume of the high-fat and low-carbohydrate diet + radiotherapy group was (220.88±130.05) mm3, which was significantly smaller than that of the normal diet group [(504.37±328.48) mm3, P=0.042)] and the high-fat, low-carbohydrate diet group [(534.26±230.42) mm3, P=0.016], but there was no statistically significant difference compared with the normal diet + radiotherapy group [(274.64±160.97) mm3]. In the 4th week, the blood glucose values of the mice in the high-fat and low-carbohydrate diet group were lower than those in the normal diet group, with the value being (8.00±0.36) mmol/L and (9.57±0.40) mmol/L, respectively, and the difference was statistically significant (Pï¼0.05). The blood ketone values of the mice in the high-fat and low-carbohydrate diet group were higher than those in the normal diet group, with the value being (1.00±0.20) mmol/L and (0.63±0.06) mmol/L, respectively, in the second week. In the third week, the blood ketone values of the two groups of mice were (0.90±0.17) mmol/L and (0.70±0.10) mmol/L, respectively, and the difference was statistically significant (Pï¼0.05). On the 30th day after inoculation, there were no significant differences in aspartate aminotransferase, alanine aminotransferase, creatinine, and urea between the normal diet group and the high-fat, low-carbohydrate diet group (all Pï¼0.05). The hearts, livers, spleens, lungs, and kidneys of the mice in each group had no obvious toxic changes and tumor metastasis. In the high-fat and low-carbohydrate diet + radiotherapy group, the expression of CD8 was up-regulated in the tumor tissues of mice, and the expressions of PD-1, CD34, LYVE-1, and collagen fibers were down-regulated. The proportion of CD8+ T cells in the paratumoral lymph nodes of the high-fat and low-carbohydrate diet + radiotherapy group was (25.13±0.97)%, higher than that of the normal diet group [(20.60±2.23)%, Pï¼0.050] and the normal diet + radiotherapy group [(19.26±3.07)%, Pï¼0.05], but there was no statistically significant difference with the high-fat and low-carbohydrate diet group [(22.03±1.75)%, Pï¼0.05]. The proportion, of CD4+ T cells in the lymph nodes adjacent to the tumor in the normal diet + radiotherapy group (31.33±5.16)% and the high-fat and low-carbohydrate diet + radiotherapy group (30.63±1.70)% were higher than that in the normal diet group [(20.27±2.15)%, Pï¼0.05] and the high-fat and low-carbohydrate diet group (23.70±2.62, Pï¼0.05). Treg cells accounted for the highest (16.58±5.10)% of T cells in the para-tumor lymph nodes of the normal diet + radiotherapy group, but compared with the normal diet group, the high-fat and low-carbohydrate diet group, and the high-fat and low-carbohydrate diet + radiotherapy group, there was no statistically significant difference (all Pï¼0.05). Conclusion: High-fat and low-carbohydrate diet plus radiotherapy can enhance the recruitment and function of immune effector cells in the tumor microenvironment, inhibit tumor microangiogenesis, and thus inhibit tumor growth.
Assuntos
Carcinoma Pulmonar de Lewis , Dieta com Restrição de Carboidratos , Dieta Hiperlipídica , Camundongos Endogâmicos C57BL , Microambiente Tumoral , Animais , Carcinoma Pulmonar de Lewis/radioterapia , Carcinoma Pulmonar de Lewis/metabolismo , Camundongos , Dieta Hiperlipídica/efeitos adversos , Dieta com Restrição de Carboidratos/métodos , Carga Tumoral , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologiaRESUMO
BACKGROUND: Tumor-associated macrophages (TAMs) play a pivotal role in reshaping the tumor microenvironment following radiotherapy. The mechanisms underlying this reprogramming process remain to be elucidated. METHODS: Subcutaneous Lewis lung carcinoma (LLC) murine model was treated with hypofrationated radiotherapy (8 Gy × 3F). Single-cell RNA sequencing was utilized to identify subclusters and functions of TAMs. Multiplex assay and enzyme-linked immunosorbent assay (ELISA) were employed to measure serum chemokine levels. Bindarit was used to inhibit CCL8, CCL7, and CCL2. The infiltration of TAMs after combination treatment with hypofractionated radiotherapy and Bindarit was quantified with flow cytometry, while the influx of CD206 and CCL8 was assessed by immunostaining. RESULTS: Transcriptome analysis identified a distinct subset of M2-like macrophages characterized by elevated Ccl8 expression level following hypofractionated radiotherapy in LLC-bearing mice. Remarkbly, hypofractionated radiotherapy not only promoted CCL8high macrophages infiltration but also reprogrammed them by upregulating immunosuppressive genes, thereby fostering an immunosuppressive tumor microenvironment. Additioinally, hypofractionated radiotherapy enhanced the CCL signaling pathway, augmenting the pro-tumorigenic functions of CCL8high macrophages and boosting TAMs recruitment. The adjunctive treatment combining hypofractionated radiotherapy with Bindarit effectively reduced M2 macrophages infiltration and prolonged the duration of local tumor control. CONCLUSIONS: Hypofractionated radiotherapy enhances the infiltration of CCL8high macrophages and amplifies their roles in macrophage recruitment through the CCL signaling pathway, leading to an immunosuppressive tumor microenvironment. These findings highlight the potential of targeting TAMs and introduces a novel combination to improve the efficacy of hypofractionated radiotherapy.
Assuntos
Carcinoma Pulmonar de Lewis , Macrófagos , Animais , Camundongos , Carcinoma Pulmonar de Lewis/radioterapia , Carcinoma Pulmonar de Lewis/patologia , Linhagem Celular Tumoral , Indazóis/farmacologia , Macrófagos/metabolismo , Propionatos/farmacologia , Análise de Sequência de RNA , Microambiente Tumoral/genética , Análise de Célula Única , Quimiocina CCL8RESUMO
Recent in vitro experiments showed that combined treatment with MHY1485, a low-molecular-weight compound, and X-ray irradiation significantly increased apoptosis and senescence in tumor cells, which was associated with oxidative stress, endoplasmic reticulum (ER) stress and p21 stabilization, compared to radiation treatment alone. However, evidence for MHY1485 treatment-mediated suppression of tumor growth in animals is still lacking. Furthermore, it has been shown that ER stress enhances immunogenic cell death (ICD) in tumor cells, as it can exert a favorable influence on the anti-cancer immune system. In the present study, we examined whether co-treatment of MHY1485 and X-ray irradiation induces ICD and in vivo tumor growth suppression using the CT26 and Lewis lung carcinoma murine tumor cell lines. We found that MHY1485 + X-ray treatment promotes ICD more effectively than X-ray treatment alone. MHY1485 suppresses tumor growth in vivo under co-treatment with X-rays and increases INF-γ, tumor necrosis factor, interleukin-2 and interleukin-12 levels in the spleen as well as the presence of CD8+ cells in the tumor. The results suggest that MHY1485 treatment leads to the conversion of irradiated tumors into effective vaccines. Thus, MHY1485 is a promising lead compound for use in combination with radiotherapy.
Assuntos
Carcinoma Pulmonar de Lewis , Morte Celular Imunogênica , Morfolinas , Triazinas , Animais , Camundongos , Carcinoma Pulmonar de Lewis/radioterapia , Carcinoma Pulmonar de Lewis/patologia , Linfócitos T CD8-Positivos , Linhagem Celular TumoralRESUMO
PURPOSE: Our previous study revealed that elevated C-C motif chemokine ligand 2 (CCL2) secretion by irradiated cancer cells recruited C-C motif chemokine receptor 2 (CCR2)-positive myeloid cells and polarized M2-type tumor-associated macrophages (TAMs), promoting lung metastasis in an established mouse model. This study investigated the impact of CCL2 and TAMs on adaptive immunity. METHODS: We assessed the influence of CCL2 and TAMs on adaptive immunity through two ectopic allograft mouse models constructed with MB49 bladder cancer cells and Lewis lung carcinoma cells. Both models exhibited delayed primary tumor growth following radiation therapy (RT), but RT promoted the development of pulmonary metastases in C57BL/6 mice. Additionally, we employed a direct coculture system to investigate the interaction between macrophages and target cells in the context of adaptive immunity. RESULTS: C-C motif chemokine receptor 4 (CCR4)-positive regulatory T cells (Tregs) were recruited to the postirradiated tumor microenvironment (TME). Utilizing a CCR4 antagonist to inhibit CCL2-CCR4 activation reversed the infiltration of CCR4 + Tregs and reduced the incidence of pulmonary metastases. In addition, a positive feedback loop between M2-type TAMs and Tregs was observed. The combined blockade of the CCL2-CCR4 and CCL2-CCR2 signaling pathways further decreased the risk of RT-promoted lung metastasis. CONCLUSION: The recruitment of CCR4 + Tregs to the postirradiated TME increases the metastatic potential of tumor cells through increased interactions with M2-type TAMs. A significant reduction in post-RT lung metastases in ectopic mouse models was achieved by disrupting the recruitment of both CCR4 + Tregs and CCR2 + myeloid cells, which are TAM precursors.
Assuntos
Carcinoma Pulmonar de Lewis , Neoplasias Pulmonares , Animais , Camundongos , Humanos , Macrófagos Associados a Tumor , Quimiocinas CC , Linfócitos T Reguladores , Camundongos Endogâmicos C57BL , Carcinoma Pulmonar de Lewis/radioterapia , Receptores de Quimiocinas , Neoplasias Pulmonares/radioterapia , Microambiente Tumoral , Linhagem Celular Tumoral , Receptores CCR4RESUMO
PURPOSE: Ablative radiation therapy (RT) is an important strategy to eliminate primary tumor and can potentially induce the abscopal effect. Human serum albumin nanoparticle (NP) was used for controlled release of cisplatin to decrease cisplatin's systemic toxicity, and gold (Au) was added to increase RT-induced immunogenic cell death and potentiate the abscopal antitumor immunity. METHODS AND MATERIALS: The designed albumin-based cisplatin-conjugated AuNPs were administered concurrently with ablative RT. C57BL/6 mice implanted with syngeneic murine Lewis lung carcinoma or murine MB49 tumor models were treated with ablative RT (12 Gy per fraction for 2 fractions, total 24 Gy), cisplatin, or Au-cisplatin NPs. RESULTS: Combining ablative RT with cisplatin or Au-cisplatin NPs both destroyed the primary tumor effectively and elicited immunogenic cell death accompanied by release of danger-associated molecular patterns. This enhanced recruitment of effector tumor-infiltrating immune cells, including natural killer T cells and CD8+ T cells, and elicited an increased percentage of professional antigen-presenting CD11c+ dendritic cells. Transient weight loss, accompanying hepatotoxicity, nephrotoxicity, and hematopoietic suppression, was observed as a systemic adverse event in the cisplatin but not the Au-cisplatin NPs group. Cisplatin and Au-cisplatin NPs both showed equivalent ability to reduce metastatic potential when combined with ablative RT, confirmed by suppressed unirradiated flank tumor growth and decreased metastatic lung tumor burden, which translated to improved survival. Mobilization and abundance of effector tumor-infiltrating immune cells including CD8+ T cells and dendritic cells were observed in the distant lung tumor microenvironment after ablative RT with cisplatin or Au-cisplatin NPs, demonstrating increased antitumor immunotherapeutic activity as an abscopal effect. CONCLUSIONS: Compared with cisplatin, the albumin-based Au-cisplatin NPs exhibited equivalent but no superior antitumor immunotherapeutic activity while reducing systemic adverse events and can be safely administered concurrently with ablative RT. Alternative NP formulations may be designed to further improve anticancer outcomes.
Assuntos
Carcinoma Pulmonar de Lewis , Nanopartículas Metálicas , Animais , Camundongos , Humanos , Cisplatino/farmacologia , Ouro , Camundongos Endogâmicos C57BL , Microambiente Tumoral , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Linfócitos T CD8-Positivos , Albuminas , Linhagem Celular TumoralRESUMO
BACKGROUND AND PURPOSE: Abnormal vascular network of tumor can create a hypoxic microenvironment, and reduce radiotherapy sensitivity. Normalization of tumor vasculature can be a new therapeutic strategy for sensitizing radiotherapy. This study aimed to explore the effect of apatinib on vascular normalization, as well as the syngeneic effect with radiotherapy on lung cancer. MATERIALS AND METHODS: Lewis lung carcinoma (LLC) xenograft-bearing female C57BL/6 mice were treated with different doses of apatinib (30, 60, and 120 mg/kg per day) and/or radiation therapy (8 Gy/1F) and then sacrificed to harvest tumor tissue for immunohistochemical test. Further 18 F-FMISO micro- PET in vivo explored the degree of hypoxia. RESULTS: Immunohistochemistry of CD31 and alpha-smooth muscle actin (α-SMA) proved that low-dose apatinib can normalize vasculature in tumor, especially on Day 10. Tissue staining of hypoxyprobe-1 and 18 F-FMISO micro- PET in vivo showed that 60 mg/kg/day of apatinib significantly alleviates hypoxia. Moreover, this study further proved that low-dose apatinib (60 mg/kg/day) can enhance the radio-response of LLC xenograft mice. CONCLUSION: Our data suggested that low- dose apatinib can successfully induce a vascular normalization window and function as a radio- sensitizer in the lung cancer xenografts model.
Assuntos
Carcinoma Pulmonar de Lewis , Neoplasias Pulmonares , Radiossensibilizantes , Humanos , Feminino , Animais , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Radiossensibilizantes/farmacologia , Hipóxia , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Linhagem Celular Tumoral , Microambiente TumoralRESUMO
BACKGROUND: Radioimmunotherapy has become one of the most promising strategies for cancer treatment. Preclinical and clinical studies have demonstrated that antiangiogenic therapy can improve the efficacy of immunotherapy and sensitize radiotherapy through a variety of mechanisms. However, it is undefined whether angiogenesis inhibitors can enhance the effect of radioimmunotherapy. In this study, we aim to explore the role of anlotinib (AL3818) on the combination of radiotherapy and immune checkpoint inhibitors in Lewis lung carcinoma mouse. METHODS: C57BL/6 mouse subcutaneous tumor model was used to evaluate the ability of different treatment regimens in tumor growth control. Immune response and immunophenotyping including the quantification and activation were determined by flow cytometry, multiplex immunofluorescence, and multiplex immunoassay. RESULTS: Triple therapy (radiotherapy combined with anti-PD-L1 and anlotinib) increased tumor-infiltrating lymphocytes and reversed the immunosuppressive effect of radiation on the tumor microenvironment in mouse model. Compared with radioimmunotherapy, the addition of anlotinib also boosted the infiltration of CD8+ T cells and M1 cells and caused a decrease in the number of MDSCs and M2 cells in mice. The levels of IFN-gamma and IL-18 were the highest in the triple therapy group, while the levels of IL-23, IL-13, IL-1 beta, IL-2, IL-6, IL-10, and Arg-1 were significantly reduced. NF-κB, MAPK, and AKT pathways were downregulated in triple therapy compared with radioimmunotherapy. Thus, the tumor immune microenvironment was significantly improved. As a consequence, triple therapy displayed greater benefit in antitumor efficacy. CONCLUSION: Our findings indicate that anlotinib might be a potential synergistic treatment for radioimmunotherapy to achieve better antitumor efficacy in NSCLC patients by potentiating the tumor immune microenvironment.
Assuntos
Antígeno B7-H1/antagonistas & inibidores , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Inibidores de Checkpoint Imunológico/administração & dosagem , Indóis/administração & dosagem , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Quinolinas/administração & dosagem , Radioimunoterapia/métodos , Microambiente Tumoral/imunologia , Animais , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/efeitos da radiação , Carcinoma Pulmonar de Lewis/imunologia , Linhagem Celular Tumoral , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Neoplasias Pulmonares/imunologia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Dosagem Radioterapêutica , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Transdução de Sinais/efeitos da radiação , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/efeitos da radiaçãoRESUMO
The combination of radiotherapy (RT) with immunotherapy represents a promising treatment modality for non-small cell lung cancer (NSCLC) patients. As only a minority of patients shows a persistent response today, a spacious optimization window remains to be explored. Previously we showed that fractionated RT can induce a local immunosuppressive profile. Based on the evolving concept of an immunomodulatory role for vagal nerve stimulation (VNS), we tested its therapeutic and immunological effects alone and in combination with fractionated RT in a preclinical-translational study. Lewis lung carcinoma-bearing C57Bl/6 mice were treated with VNS, fractionated RT or the combination while a patient cohort with locally advanced NSCLC receiving concurrent radiochemotherapy (ccRTCT) was enrolled in a clinical trial to receive either sham or effective VNS daily during their 6 weeks of ccRTCT treatment. Preclinically, VNS alone or with RT showed no therapeutic effect yet VNS alone significantly enhanced the activation profile of intratumoral CD8+ T cells by upregulating their IFN-γ and CD137 expression. In the periphery, VNS reduced the RT-mediated rise of splenic, but not blood-derived, regulatory T cells (Treg) and monocytes. In accordance, the serological levels of protumoral CXCL5 next to two Treg-attracting chemokines CCL1 and CCL22 were reduced upon VNS monotherapy. In line with our preclinical findings on the lack of immunological changes in blood circulating immune cells upon VNS, immune monitoring of the peripheral blood of VNS treated NSCLC patients (n=7) did not show any significant changes compared to ccRTCT alone. As our preclinical data do suggest that VNS intensifies the stimulatory profile of the tumor infiltrated CD8+ T cells, this favors further research into non-invasive VNS to optimize current response rates to RT-immunotherapy in lung cancer patients.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Carcinoma Pulmonar de Lewis/terapia , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Carcinoma Pulmonar de Células não Pequenas/terapia , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/terapia , Estimulação do Nervo Vago , Idoso , Animais , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/patologia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Terapia Combinada , Feminino , Humanos , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Linfócitos do Interstício Tumoral/imunologia , Masculino , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Carga TumoralRESUMO
PURPOSE: The hypoxic microenvironments of solid tumours are complex and reduce the susceptibility of cancer cells to chemo- and radiotherapy. Conventional radiosensitisers have poor specificity, unsatisfactory therapeutic effects, and significant side effects. Anaerobic bacteria colonise and destroy hypoxic areas of the tumour and consequently enhance the effects of radiation. METHODS: In this study, we treated a Lewis lung carcinoma transplant mouse model with Bifidobacterium infantis (Bi) combined with its specific monoclonal antibody (mAb) and radiotherapy (RT) to investigate its ability to radiosensitise the tumour. The tumour metabolism and hypoxia in the tumour tissue were monitored by micro-18F-FDG and 18F-FMISO PET/CT imaging. Immunohistochemistry was used to detect phosphorylated histone (γ-H2AX), proliferation (Ki-67), platelet endothelial cell adhesion molecules (CD31), tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α), and glucose transporter 1 (Glut-1) levels. RESULTS: Tumour growth was slowed and survival time was markedly prolonged in mice subjected to the combination of B. infantis, specific antibody, and radiotherapy. Levels of HIF-1α, Glut-1, Ki-67, and CD31 expression, as well as uptake of FDG and FMISO, were the lowest in the combination-treated mice. In contrast, γ-H2AX and TNF-α expression levels were elevated and hypoxia in tumour tissue was reduced compared with controls. CONCLUSION: In conclusion, our data indicated that the curative effect of radiotherapy for lung cancer was enhanced by pre-treating mice with a combination of B. infantis and its specific monoclonal antibody.
Assuntos
Anticorpos Antibacterianos/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Bifidobacterium longum subspecies infantis , Carcinoma Pulmonar de Lewis/radioterapia , Radiossensibilizantes/uso terapêutico , Animais , Bifidobacterium longum subspecies infantis/imunologia , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/mortalidade , Carcinoma Pulmonar de Lewis/patologia , Hipóxia Celular , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Glucose/metabolismo , Histonas/análise , Antígeno Ki-67/análise , Camundongos , Camundongos Endogâmicos C57BL , Tomografia por Emissão de Pósitrons combinada à Tomografia ComputadorizadaRESUMO
PURPOSE: Radiation therapy (RT) is widely used in the treatment of cancer. Unfortunately, RT alone is insufficient to control the disease in most cases, as regrowth after irradiation still occur. Thus, it would be meaningful to explore the underlying mechanism of tumor regrowth after irradiation. Myeloid-derived suppressor cells (MDSCs) contribute to the immunosuppressive tumor microenvironment and hinder the therapeutic efficacy of RT. However, it is unclear whether MDSCs-mediated immune suppression contributes to local relapse after irradiation. In this article, we tried to figure out how MDSCs sabotage the therapeutic effect of RT, and tried to determine the potential synergistic effect of combination between targeting MDSCs and RT. METHODS AND MATERIALS: A syngeneic murine model of Lewis lung cancer was used. The abundance of tumor infiltrating MDSCs and tumor growth after irradiation was assessed. The percentage and functional state of CD8+ T cells were measured by flow cytometry, with or without polymorphonuclear (PMN)-MDSCs depletion. Arginase 1 (ARG1) expression and activity of MDSCs were examined by hematoxylin and eosin staining and flow cytometry. ARG1 inhibitor and phosphodiesterase 5 inhibitor sildenafil were administered after RT to figure out the underlying mechanism of MDSCs-mediated immunosuppression. RESULTS: We demonstrated that irradiation recruited MDSCs, especially the polymorphonuclear subset, into the tumor microenvironment. PMN-MDSCs inhibited the CD8+ T cell response by elevating ARG1 expression. Selective depletion of PMN-MDSCs or inhibition on ARG1 promoted the infiltration and activation of intratumoral CD8+ T cells, and delayed tumor regrowth after irradiation. We showed that sildenafil reduced the accumulation and ARG1 expression of PMN-MDSCs after irradiation, thus abrogating the MDSCs-mediated immunosuppression. CONCLUSIONS: Our results have suggested that PMN-MDSCs participate in the irradiation-induced immune suppression through ARG1 activation. We have also found that sildenafil has the potential to facilitate antitumor immunity, which provides a new alternative to delay tumor recurrence after RT.
Assuntos
Arginase/metabolismo , Linfócitos T CD8-Positivos/imunologia , Carcinoma Pulmonar de Lewis/radioterapia , Células Supressoras Mieloides/fisiologia , Recidiva Local de Neoplasia/prevenção & controle , Microambiente Tumoral/imunologia , Animais , Arginase/antagonistas & inibidores , Carcinoma Pulmonar de Lewis/imunologia , Movimento Celular , Progressão da Doença , Citometria de Fluxo , Tolerância Imunológica , Ativação Linfocitária , Linfócitos do Interstício Tumoral/imunologia , Camundongos , Células Supressoras Mieloides/citologia , Células Supressoras Mieloides/efeitos dos fármacos , Células Supressoras Mieloides/efeitos da radiação , Inibidores da Fosfodiesterase 5/farmacologia , Citrato de Sildenafila/farmacologiaRESUMO
PURPOSE: To investigate whether the vascular collapse in tumors by conventional dose rate (CONV) irradiation (IR) would also occur by the ultra-high dose rate FLASH IR. METHODS AND MATERIALS: Lewis lung carcinoma (LLC) cells were subcutaneously implanted in mice. This was followed by CONV or FLASH IR at 15 Gy. Tumors were harvested at 6 or 48 hours after IR and stained for CD31, phosphorylated myosin light chain (p-MLC), γH2AX (a surrogate marker for DNA double strand break), intracellular reactive oxygen species (ROS), or immune cells such as myeloid and CD8α T cells. Cell lines were irradiated with CONV IR for Western blot analyses. ML-7 was intraperitoneally administered daily to LLC-bearing mice for 7 days before 15 Gy CONV IR. Tumors were similarly harvested and analyzed. RESULTS: By immunostaining, we observed that CONV IR at 6 hours resulted in constricted vessel morphology, increased expression of p-MLC, and much higher numbers of γH2AX-positive cells in tumors, which were not observed with FLASH IR. Mechanistically, MLC activation by ROS is unlikely, because FLASH IR produced significantly more ROS than CONV IR in tumors. In vitro studies demonstrated that ML-7, an inhibitor of MLC kinase, abrogated IR-induced γH2AX formation and disappearance kinetics. Lastly, we observed that CONV IR when combined with ML-7 produced some effects similar to FLASH IR, including reduction in the vasculature collapse, fewer γH2AX-positive cells, and increased immune cell influx to the tumors. CONCLUSIONS: FLASH IR produced novel changes in the tumor microenvironment that were not observed with CONV IR. We believe that MLC activation in tumors may be responsible for some of the microenvironmental changes differentially regulated between CONV and FLASH IR.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Cadeias Leves de Miosina/efeitos da radiação , Microambiente Tumoral/efeitos da radiação , Animais , Azepinas/administração & dosagem , Vasos Sanguíneos/patologia , Vasos Sanguíneos/efeitos da radiação , Linfócitos T CD8-Positivos/citologia , Carcinoma Pulmonar de Lewis/irrigação sanguínea , Carcinoma Pulmonar de Lewis/metabolismo , Histonas/metabolismo , Histonas/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Cadeias Leves de Miosina/antagonistas & inibidores , Cadeias Leves de Miosina/metabolismo , Naftalenos/administração & dosagem , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/efeitos da radiação , Radioterapia/métodos , Dosagem Radioterapêutica , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/efeitos da radiaçãoRESUMO
BACKGROUND: Subcutaneous mouse tumour models are widely used for the screening of novel antitumour treatments, although these models are poor surrogate models of human cancers. METHODS: We compared the antitumour efficacy of the combination of ionising radiation (IR) with two DNA damage response inhibitors, the PARP inhibitor olaparib and the ATR inhibitor AZD6738 (ceralasertib), in subcutaneous versus orthotopic cancer models. RESULTS: Olaparib delayed the growth of irradiated Lewis lung carcinoma (LL2) subcutaneous tumours, in agreement with previous reports in human cell lines. However, the olaparib plus IR combination showed a very narrow therapeutic window against LL2 lung orthotopic tumours, with nearly no additional antitumour effect compared with that of IR alone, and tolerability issues emerged at high doses. The addition of AZD6738 greatly enhanced the efficacy of the olaparib plus IR combination treatment against subcutaneous but not orthotopic LL2 tumours. Moreover, olaparib plus AZD6738 administration concomitant with IR even worsened the response to radiation of head and neck orthotopic tumours and induced mucositis. CONCLUSIONS: These major differences in the responses to treatments between subcutaneous and orthotopic models highlight the importance of using more pathologically relevant models, such as syngeneic orthotopic models, to determine the most appropriate therapeutic approaches for translation to the clinic.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Animais , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quinase 1 do Ponto de Checagem/metabolismo , Quimiorradioterapia , Feminino , Indóis , Camundongos , Camundongos Endogâmicos C57BL , Morfolinas , Ftalazinas/administração & dosagem , Piperazinas/administração & dosagem , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Pirimidinas/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas , Sulfóxidos/administração & dosagemRESUMO
Radiation therapy remains one of the main treatments for cancer. However, conventional radiotherapy not only manifests a low radiation accumulation in the tumor site, but also displays numerous negative effects. The most serious clinical problem is the radiotherapy resistance leading to cancer deterioration. As an important gaseous signal molecule, nitric oxide (NO) has been widely studied for its role in regulating angiogenesis, improving hypoxia, and inhibiting tumor growth. However, due to the unstable characteristic, the application of NO in cancer therapy is still limited. Here, we designed a micellar system formed by a NO donor, D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS)-NO, for enabling sustained NO release to efficiently deliver NO into the tumor area. TPGS-NO could accumulate in the tumor site for extended circulation, thereby releasing NO to exert antitumor effects and enhance radiotherapy effects under low-oxygen conditions. It demonstrated the increased sensitivity of radiotherapy through enhancing tumor angiogenesis appropriately reducing tumor area hypoxia, which significantly induced tumor cell apoptosis and inhibited its repair during radiation. This work may show great potential in synergistic radiotherapy against cancer by facile NO donor administration.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/farmacologia , Tolerância a Radiação , Radiossensibilizantes/farmacologia , Hipóxia Tumoral , Vitamina E/química , Animais , Apoptose/efeitos dos fármacos , Carcinoma Pulmonar de Lewis/diagnóstico por imagem , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/patologia , Células Cultivadas , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Micelas , Neovascularização Patológica , Óxido Nítrico/química , Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/química , Doadores de Óxido Nítrico/metabolismo , Radiossensibilizantes/química , Radiossensibilizantes/metabolismoRESUMO
BACKGROUND: Sublethal radiation induces matrix metalloproteinase 9 (MMP-9)-mediated radioresistance in Lewis lung carcinoma (LLC) cells and their metastatic dissemination. We aim to determine if EGFR/HER2 activation associates with MMP-9-mediated radioresistance and invasiveness in irradiated LLC cells. METHODS: LLC cells were treated with erlotinib or afatinib followed by sublethal radiation. After irradiation, we examined the phosphorylation of EGFR/HER2 and MMP-9 expression. Colony formation assay determined if the kinase inhibitors sensitize LLC cells to radiation. Matrigel-coated Boyden chamber assay assessed cellular invasiveness. Resulting tumors of wild-type LLC cells or HER2 knock-down mutant cells were irradiated to induce pulmonary metastases. RESULTS: Afatinib more effectively sensitized LLC cells to radiation and decreased invasiveness by inhibiting phosphorylation of EGFR, HER2, Akt, ERK, and p38, and down-regulating MMP-9 when compared to erlotinib. Afatinib abolished radiation-induced lung metastases in vivo. Furthermore, LLC HER2 knock-down cells treated with radiation had growth inhibition. CONCLUSION: Dual inhibition of radiation-activated EGFR and HER2 signaling by afatinib suppressed the proliferation and invasion of irradiated LLC cells. Increased radiosensitivity and decreased metastatic dissemination were observed by pharmacological or genetic HER2 inhibition in vivo. These findings indicate that HER2 plays a pivotal role in enhancing radioresistance and reducing metastatic potential of LLC cells.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Tolerância a Radiação/efeitos dos fármacos , Receptor ErbB-2/antagonistas & inibidores , Afatinib/farmacologia , Animais , Carcinoma Pulmonar de Lewis/patologia , Linhagem Celular Tumoral , Receptores ErbB/antagonistas & inibidores , Humanos , Masculino , Metaloproteinase 9 da Matriz/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Invasividade Neoplásica , Metástase Neoplásica , Fosforilação , Receptor ErbB-2/fisiologia , Transdução de SinaisRESUMO
PURPOSE: Radiotherapy (RT) is frequently used for local control of solid tumors using equal dose per fraction. Recently, single high-dose radiation has been used for ablation of solid tumors. In this report, we provide a novel immunological basis for radiation dose fractionation consisting of a single high-dose radiotherapy, followed by postablation modulation (PAM) with four daily low-dose fractions (22 Gy + 0.5 Gy × 4) to reprogram the tumor microenvironment by diminishing immune suppression, enabling infiltration of effector cells and increasing efficacy of tumor control. EXPERIMENTAL DESIGN: Palpable 3LL and 4T1 tumors in C57Bl/6 and Balb/c mice were irradiated with the Small-Animal Radiation Research Platform irradiator, and tumor growth and survival were monitored. Immunomodulation of tumor and immune cells in vitro and in vivo characterization of tumor-infiltrating immune effector cells were performed by FACS. For systemic application of PAM-RT, whole-lung irradiation was administered in 4T1-bearing Balb/c mice. RESULTS: We report significant tumor growth delays and increased survival in 3LL tumor-bearing mice with PAM. Primary tumor PAM-RT increased infiltration of immune effector cells and decreased Treg in irradiated tumors and secondary lymphoid organs. In a model of murine metastatic breast cancer (4T1), we demonstrated that systemic PAM-RT to the whole lung, 12 days after primary tumor ablative radiotherapy, increased survival with suppression of pulmonary metastases. CONCLUSIONS: We provide a novel immunologic basis for radiation dose fractionation consisting of a single high dose of radiotherapy followed by daily low-dose PAM-RT fractionation to improve the immunogenic potential of ablative radiotherapy.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Linfócitos do Interstício Tumoral/imunologia , Neoplasias Mamárias Experimentais/radioterapia , Microambiente Tumoral/imunologia , Técnicas de Ablação/métodos , Animais , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/cirurgia , Linhagem Celular Tumoral , Fracionamento da Dose de Radiação , Feminino , Imunomodulação/efeitos da radiação , Linfócitos do Interstício Tumoral/efeitos da radiação , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/cirurgia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Taxa de Sobrevida , Microambiente Tumoral/efeitos da radiaçãoRESUMO
Previous studies suggest that radiotherapy (RT) can induce immune activation, which not only reduces the progression of tumors, but also causes the release of tumor antigens. The combination of RT and immune checkpoint blockade, such as the inhibition of programmed cell death 1 (PD1) and programmed cell death ligand 1 (PDL1), has been demonstrated to yield impressive response rates. However, a substantial proportion of patients develop resistance such therapies. Previous studies have shown that indoleamine 2,3dioxygenase (IDO) causes T cell exhaustion and increased formation of regulatory T cells (Tregs), upregulating the expression of inhibitory receptors and ligands. Therefore, the application of IDO inhibitors combined with RT may have a synergistic effect by relieving immunosuppression. Lewis lung cancer cellbearing mice were treated with the IDO inhibitor 1methyltryptophan (1MT) and/or 10 Gy RT. Tumor size was measured every day, flow cytometry was performed to measure the expression of dendritic cell (DC) maturation markers, inhibitory receptors, ligands, cytotoxic T cells and Treg phenotypic markers. Reverse transcriptionquantitative PCR was used to evaluate the mRNA expression levels of IDO, PDL1, PD1, T cell immunoglobulin domain and mucin domain 3 (TIM3), B and Tlymphocyte attenuator (BTLA) and galectin9. Compared with the control group, treatment with 1MT or RT reduced tumor growth, however, the combination therapy was more effective than either treatment alone. Flow cytometry showed the upregulation of CD80, CD86 and the major histocompatibility complex II in spleen DCs and the concurrent downregulation of CD4, CD25 and forkhead box protein P3 in lymphocytes in the treatment groups. Compared with the control group, inhibitory receptors and ligands that affect DCs and T cells were observed, expression levels of PDL1, PD1, TIM3, BTLA and galectin9 are decreased in treatment group compared with control. IDO inhibition synergized with RT to downregulate Tregs, inhibitory receptors and ligands to prevent T cell exhaustion. By activating DCs and T cells, this combination therapy may strongly enhance antitumor immunity and inhibit tumor progression.
Assuntos
Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Animais , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/imunologia , Terapia Combinada , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/efeitos da radiação , Resistencia a Medicamentos Antineoplásicos/imunologia , Citometria de Fluxo , Galectinas/imunologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Receptor Celular 2 do Vírus da Hepatite A/genética , Indolamina-Pirrol 2,3,-Dioxigenase/antagonistas & inibidores , Ligantes , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Receptores Imunológicos/genética , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Triptofano/análogos & derivados , Triptofano/farmacologiaRESUMO
Treatment of tumors with ionizing radiation stimulates an antitumor immune response partly dependent on induction of IFNs. These IFNs directly enhance dendritic cell and CD8+ T cell activity. Here we show that resistance to an effective antitumor immune response is also a result of IFN signaling in a different cellular compartment of the tumor, the cancer cells themselves. We abolished type I IFN signaling in cancer cells by genetic elimination of its receptor, IFNAR1. Pronounced immune responses were provoked after ionizing radiation of tumors from 4 mouse cancer cell lines with Ifnar1 knockout. This enhanced response depended on CD8+ T cells and was mediated by enhanced susceptibility to T cell-mediated killing. Induction of Serpinb9 proved to be the mechanism underlying control of susceptibility to T cell killing after radiation. Ifnar1-deficient tumors had an augmented response to anti-PD-L1 immunotherapy with or without radiation. We conclude that type I IFN can protect cancer cells from T cell-mediated cytotoxicity through regulation of Serpinb9. This result helps explain why radiation of tumors can stimulate antitumor immunity yet also result in resistance. It further suggests potential targets for intervention to improve therapy and to predict responses.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/efeitos da radiação , Interferon Tipo I/imunologia , Animais , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/radioterapia , Linhagem Celular Tumoral , Citotoxicidade Imunológica/efeitos da radiação , Feminino , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/radioterapia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Nus , Neoplasias Experimentais/genética , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/radioterapia , Receptor de Interferon alfa e beta/deficiência , Receptor de Interferon alfa e beta/genética , Receptor de Interferon alfa e beta/imunologia , Serpinas/genética , Serpinas/imunologia , Transdução de Sinais/imunologia , Transdução de Sinais/efeitos da radiação , Microambiente Tumoral/genética , Microambiente Tumoral/imunologia , Microambiente Tumoral/efeitos da radiaçãoRESUMO
PURPOSE: The limitation of hypofractionated radiation efficacy is due partly to the immunosuppressive tumor microenvironment. Indoleamine 2,3-dioxygenase 1 (IDO1) is an important regulator of tumor immune suppression. We evaluated the effects of IDO1 in hypofractionated radiation using a Lewis lung carcinoma (LLC) mouse model and tested whether IDO1 inhibition could sensitize those tumors to hypofractionated radiation. METHODS AND MATERIALS: Bilateral LLC tumors were established in C57BL/6 mice. Primary tumors were treated with 3 fractions of either 12 Gy or 6 Gy, and the IDO1 inhibitor INCB023843 was given starting on the first day of radiation. Plasma tryptophan and kynurenine levels were quantified by liquid chromatography and tandem mass spectrometry. Tumor-infiltrating immune cells were isolated from the tumors, stained, and quantified by flow cytometry. RESULTS: The combination of INCB023843 and three 12-Gy fractions led to better tumor control and survival than radiation alone; INCB023843 plus three 6-Gy fractions had no benefit. IDO1 expression by tumor-infiltrating immune cells was increased by three 12-Gy doses and inhibited by the addition of INCB023843. Nearly all IDO1+ immune cells were also F4/80+. Percentages of IDO1+F4/80+ immune cells were drastically increased by three 12-Gy fractions and by three 6-Gy fractions, but only INCB023843 combined with three 12-Gy fractions reduced those percentages. IDO1+F4/80+ immune cells were further found to be CD11b+, Gr1-intermediate-expressing, CD206-, and CD11c- (ie, myeloid-derived suppressor cells). Three 12-Gy fractions also increased the percentages of tumor-infiltrating T regulatory cells and CD8+ T cells, but adding INCB023843 did not affect those percentages. CONCLUSIONS: In addition to its immune activation effects, hypofractionated radiation induced "rebound immune suppression" in the tumor microenvironment by activating and recruiting IDO1-expressing myeloid-derived suppressor cells in a dose-dependent manner. Adding an IDO1 inhibitor to hypofractionated radiation reduced the percentages of these cells, overcame the immune suppression, and sensitized LLC tumors to hypofractionated radiation.
Assuntos
Carcinoma Pulmonar de Lewis/radioterapia , Tolerância Imunológica , Indolamina-Pirrol 2,3,-Dioxigenase/antagonistas & inibidores , Células Supressoras Mieloides/citologia , Oximas/farmacologia , Tolerância a Radiação/imunologia , Sulfonamidas/farmacologia , Microambiente Tumoral/imunologia , Animais , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/patologia , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Células Supressoras Mieloides/metabolismo , Hipofracionamento da Dose de Radiação , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/efeitos da radiação , Regulação para Cima/efeitos da radiaçãoRESUMO
The aim of this study was to explore the synergistic anti-tumor effects of cytarabine hyaluronic acid-tyramine (Ara-HA-Tyr) hydrogel conjugates and radiotherapy (RT) in the Lewis lung cancer (LLC) xenograft model, and the mechanisms involved. The radiotherapy sensitization ratio (SER) of 0.5 µg cytarabine (Ara-C) was 1.619 in the LLC cells. Ara-HA-Tyr was prepared by encapsulating Ara-C into hyaluronic acid-tyramine (HA-Tyr) conjugates. The hydrogels were formed through the oxidative coupling of tyramines by hydrogen peroxide (H2O2) and horseradish peroxidase (HRP). Mice engrafted with the LLC cells were given intra-tumoral injections of saline, Ara-C or Ara-HA-Tyr, with or without RT. The combination of Ara-HA-Tyr and RT increased survival compared to free Ara-C and RT (p < 0.05), and prolonged tumor growth delay (TGD). Furthermore, the RT + Ara-HA-Tyr combination therapy significantly reduced 18F-FDG uptake, induced cell cycle arrest at G2/M-phase, increased apoptosis and histone H2AX phosphorylation (γ-H2AX), and decreased the proliferation index (Ki67) in tumor cells compared to either monotherapy. Taken together, Ara-C encapsulated with HA-Tyr effectively sensitized tumor xenografts to RT and showed significantly less systemic toxicity. Graphical abstract In this work, Ara-C encapsulated with hyaluronic acid-tyramine conjugates (HA-Tyr) was prepared and used to investigate its synergistic anti-tumor efficacy by combination with radiotherapy in the Lewis lung cancer xenograft model. The synergistic mechanism may be related to tumor cell cycle redistribution, apoptosis and expression of histone H2AX phosphorylation.
Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/radioterapia , Citarabina/administração & dosagem , Ácido Hialurônico/administração & dosagem , Hidrogéis/administração & dosagem , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Animais , Apoptose , Carcinoma Pulmonar de Lewis/metabolismo , Ciclo Celular , Linhagem Celular Tumoral , Terapia Combinada , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Feminino , Histonas/metabolismo , Injeções Intralesionais , Neoplasias Pulmonares/metabolismo , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Targeting radiosensitizer-incorporated nanoparticles to a tumor could allow for less normal tissue toxicity with more efficient drug release, thus improving the efficacy and safety of radiation treatment. The aim of this study was to improve tumor-specific delivery and bioavailability of a nanoparticle-mediated radiosensitizer in mouse brain tumor models. METHODS: A pH-sensitive nanoparticle, chitoPEGAcHIS, was conjugated to recombinant peptide HVGGSSV that could bind to tax-interaction protein 1 (TIP-1) as a radiation-inducible receptor. Then the c-Jun N-terminal kinase (JNK) inhibitor, SP600125 was incorporated into this copolymer to fabricate a HVGGSSV-chitoPEGAcHIS-SP600125 (HVSP-NP) nanoradiosensitizer. In vitro and in vivo radiation treatment were performed using a Gamma Knife unit. The tumor targetability of HVSP-NP was estimated by optical bioluminescence. Synergistic therapeutic effects of radiation treatment and HVSP-NP were investigated in Lewis lung carcinoma (LLC) cell-bearing mouse brain tumor models. RESULTS: The SP600125 JNK inhibitor effectively reduced DNA damage repair to irradiated LLC cells. A pH sensitivity assay indicated that HVSP-NP swelled at acidic pH and increased in diameter, and its release rate gradually increased. Optical bioluminescence assay showed that radiation induced TIP-1 expression in mouse brain tumor and that the nanoradiosensitizer selectively targeted irradiated tumors. Radiation treatment with HVSP-NP induced greater apoptosis and significantly inhibited tumor growth compared to radiation alone. CONCLUSION: As a novel nanoradiosensitizer, HVSP-NP was found to be able to selectively target irradiated tumors and significantly increase tumor growth delay in LLC-bearing mouse brain tumor models. This research shows that delivering a pH-sensitive nanoradiosensitizer to a brain tumor in which TIP-1 is induced by radiation can result in improved radiosensitizer-release in an acidic microenvironment of tumor tissue and in created synergistic effects in radiation treatment.