Combined Radiation Treatment Research Articles

Combined Therapy of Pegylated G-CSF and Alxn4100TPO Improves Survival and Mitigates Acute Radiation Syndrome after Whole-Body Ionizing Irradiation Alone and Followed by Wound Trauma.

Exposure to ionizing radiation alone or combined with traumatic tissue injury is a crucial life-threatening factor in nuclear and radiological incidents. Radiation injuries occur at the molecular, cellular, tissue and systemic levels; their mechanisms, however, remain largely unclear. Exposure to radiation combined with skin wounding, bacterial infection or burns results in greater mortality than radiation exposure alone in dogs, pigs, rats, guinea pigs and mice. In the current study we observed that B6D2F1/J female mice exposed to 60Co gamma-photon radiation followed by 15% total-body-surface-area skin wounds experienced an increment of 25% higher mortality over a 30-day observation period compared to those subjected to radiation alone. Radiation exposure delayed wound healing by approximately 14 days. On day 30 post-injury, bone marrow and ileum in animals from both groups (radiation alone or combined injury) still displayed low cellularity and structural damage. White blood cell counts, e.g., neutrophils, lymphocytes, monocytes, eosinophils, basophils and platelets, still remained very low in surviving irradiated alone animals, whereas only the lymphocyte count was low in surviving combined injury animals. Likewise, in surviving animals from radiation alone and combined injury groups, the RBCs, hemoglobin, hematocrit and platelets remained low. We observed, that animals treated with both pegylated G-CSF (a cytokine for neutrophil maturation and mobilization) and Alxn4100TPO (a thrombopoietin receptor agonist) at 4 h postirradiation, a 95% survival (vehicle: 60%) over the 30-day period, along with mitigated body-weight loss and significantly reduced acute radiation syndrome. In animals that received combined treatment of radiation and injury that received pegylated G-CSF and Alxn4100TPO, survival was increased from 35% to 55%, but did not accelerate wound healing. Hematopoiesis and ileum showed significant improvement in animals from both groups (irradiation alone and combined injury) when treated with pegylated G-CSF and Alxn4100TPO. Treatment with pegylated G-CSF alone increased survival after irradiation alone and combined injury by 33% and 15%, respectively, and further delayed wound healing, but increased WBC, RBC and platelet counts after irradiation alone, and only RBCs and platelets after combined injury. Treatment with Alxn4100TPO alone increased survival after both irradiation alone and combined injury by 4 and 23%, respectively, and delayed wound healing after combined injury, but increased RBCs, hemoglobin concentrations, hematocrit values and platelets after irradiation alone and only platelets after combined injury. Taken together, the results suggest that combined treatment with pegylated G-CSF and Alxn4100TPO is effective for mitigating effects of both radiation alone and in combination with injury.

К вопросу о возможности аллогенной плацентарной терапии постовариоэктомических проявлений у больных, отягощенных гинекологическим раком, после противоопухолевого лечения

The results of a clinical-psychological prospective examination of 131 patients with cervical cancer, the uterus body and ovaries of stage I-III according to FIGO, reproductive age in total hysterovectomy and radiation suppression of ovaries isolated in three clinical groups are presented: group I - patients after combined and complex special treatment; Group II - patients after combined radiation treatment and group III - patients after combined and complex treatment, therapy of postovariochemical manifestations of which was carried out by traditional therapy. Identification of personal resources of stress-resistance was carried out using the copy-test of R.Lazarus. The intensity of oxidative processes in blood plasma was judged by the content of their carbonyl derivatives, revealed in the reaction with 2,4-dinitrophenylhydrazine. Results and discussion. For patients in the state of total hysterovarioectomy (groups I and III), the hyperactivity of the strategy Confrontation (76.8% and 76.4%, respectively) and Positive revaluation (67.8% and 72.6%) are a common phenomenon. Constructive strategies; Distant (73.8%) and Acceptance of responsibility (82.5%) are typical for patients of the II group who are in drug and radiation suppression. In the blood of all patients, increased oxidative potential was determined. Significant changes were demonstrated in the analysis of the intensity of induced (metal-catalyzed) OMB: at λ 370 nm and λ 530 nm in group I and group III (p<0.01): the level of oxidation products was significantly lower in the group II patients after SLT. Changes were demonstrated in the analysis of the intensity of induced (metal-catalyzed) OMB. The level of carbonyl groups was significantly lower in the group of patients II after SLT (p<0.01). After the therapy with allogeneic hydrolyzate of the placenta (AHP) with Melsmon of the APEC for 14 weeks, an objective orientation toward a decrease in the oxidative potential in the blood of patients was manifested. The serum level of the end products of OMB had an active decrease in comparison with the similar values in group I at λ 370 nm (1.3 times) and λ 430 nm (1.5 times); p<0.01. At λ 530 nm - groups I decrease by 1.4 times and II decrease by 1.6 times, p<0.01. The level of OMB in induced oxidation demonstrated a pronounced active decrease, especially at λ 530 (p<0.01). The study of induced AMB in the serum of Group III patients with gynecological cancer, the treatment of which was carried out by traditional methods in the PES did not show any statistical differences. In group I patients, the activity of non-constructive strategies is significantly reduced: confrontation (from 76.8% to 54.2%); flight/avoidance (from 64.2% to 38.6%). More actively, patients began to apply resources to constructive distancing strategies (activity increased from 42.4% to 68.3%); planning of problem solving (from 42.8% to 72.4%). The active decrease in the level of the carbonyl products of protein oxidation correlated with the improvement and stabilization of the psychological status in the form of non-constructive coping strategies Confrontation, Escape-avoidance in patients of group I (r=0.379, r=0.437, p<0.001) and group II (r=0.439, r=0.376, p<0.001). Conclusions. 1. In gynecological cancer cases examined in the PES state , there is an intensification of the processes of free radical oxidation of biomolecules. However, in patients with preserved ovaries, the oxidative processes are somewhat reduced. 2. Decrease in the levels of carbonyl oxidation products against the background of Melsmon therapy in patients with gynecological cancer in the state of PES testifies to the possibility of participation of the drug components in antiradical protection. 3. Evaluation of the results of sonographic monitoring of the abdominal and pelvic organs in patients included in the study did not reveal a worsening of the prognosis of the underlying disease against the background of allogeneic placental therapy. 4. Allogeneic placental therapy with Melsmon helps to improve the psychological status of gynecological cancer patients in the form of stress-overcoming.

Radiotherapy and tumor immunity

Infiltrated immune cells and cytokines in the tumor microenvironment may play different functions that appear tightly related to clinical outcomes. Radiotherapy mainly kills tumor cells through radiobiological effect, meanwhile it can indirectly change tumor immunologic microenvironment, and has a local or distant anti-tumor immunological effect cooperatively. Animal experiments and clinical trials of radiotherapy combined with immunotherapy display well applied prospects, but the mode of radiotherapy in combined treatment needs further research. Key words: Radiotherapy; Immunity

Combining fisetin and ionizing radiation suppresses the growth of mammalian colorectal cancers in xenograft tumor models.

Fisetin (3,7,3′,4′-tetrahydroxyflavone), which belongs to the flavonoid group of polyphenols and is found in a wide range of plants, has been reported to exhibit a number of biological activities in human cancer cells, including antioxidant, anti-inflammatory, antiangiogenic, anti-invasive and antiproliferative effects. Although previous in vitro studies have shown that fisetin treatment increases the apoptotic rate and enhances the radiosensitivity of human colorectal cancer cells, the in vivo effects of fisetin on tumor growth remain unclear. In the present study a murine xenograft tumor model was employed to investigate the therapeutic effects of fisetin in combination with radiation on CT-26 colon cancer cells and human HCT116 colorectal cancer cells. This revealed that intratumoral injection of fisetin significantly suppressed the growth of CT-26 tumors compared with the untreated control group, but had little effect on the growth of HCT116 tumors. However, fisetin in combination with 2-Gy radiation enhanced tumor suppressor activity in murine colon and human colorectal xenograft tumors, as compared with 2-Gy fractionated radiation administered alone for 5 days and fisetin alone. Interestingly, fisetin downregulated the expression of the oncoprotein securin in a p53-independent manner. However, securin-null HCT116 tumors showed only moderate sensitivity to fisetin treatment, and the combination of fisetin and radiation did not significantly suppress securin-null HCT116 tumor growth compared with normal HCT116 tumors. Therefore, the role of securin in mediating the effect of fisetin on colorectal cancer growth warrants further investigation. In conclusion, the results of the current study provide important preclinical data for evaluating the efficacy of fisetin and radiation combination treatment as an adjuvant chemoradiotherapy for human colorectal cancers.

Gimeracil Exerts Radiosensitizing Effects on Oral Squamous Cell Carcinoma Cells In Vitro and In Vivo.

Gimeracil or 5-chloro-2, 4-dihydroxypyridine (CDHP) has been reported to exert radiosensitization effects in cancer cells by suppressing DNA repair pathways. Here, we investigated the antitumor effect of gimeracil and radiation combination therapy against oral squamous cell carcinoma (OSCC). The antitumor activity of gimeracil and/or radiation was investigated in HSC2 and/or SAS cells by growth inhibition assays and clonogenic survival assay. The expression of DNA double-strand break repair proteins were assessed by western blotting and immunohistochemistry, also fluorescent measurements of intracellular reactive oxygen/nitrogen species (ROS/RNS) were carried out in gimeracil and/or radiation-treated HSC2 cells/tumors. Gimeracil and radiation combination treatment significantly inhibited OSCC cell/tumor growth and colony formation. Down-regulated expressions of DNA double-strand break repair proteins were observed in gimeracil and/or radiation treated cells/tumors. Additionally, the growth inhibitory effect of this combination treatment was associated with reactive oxygen species/reactive nitrogen species (ROS/RNS) generation. Gimeracil might exert radiosensitizing effects on OSCC cells.

Effect of combined treatment of radiation and tissue-specific recombinant oncolytic adenovirus on bladder cancer cells

Purpose: Gene therapy combined with radiation has shown promising potential for the treatment of tumors. This paper aimed to clarify the synergistic effect of radiotherapy combined with the bladder cancer tissue-specific oncolytic adenovirus (Ad-PSCAE-UPII-E1A) on bladder cancer cells and to study the underlying synergy mechanisms of the combined treatment.Materials and methods: The Adenovirus carrying E1A under control of UPII promoter and prostate stem cell antigen enhancer (PSCAE) were successfully constructed. The viability of bladder cancer cells BIU-87 and EJ was determined by MTT assay. The apoptotic assay was demonstrated by flow cytometry and TEM. Virus titer was determined by TCID50 assay, and proteins Mre11, Chk2-Thr68, and E1A were analyzed by Western blot method.Results: Oncolytic adenovirus combined with radiotherapy improved antitumor efficacy compared with the single treatment at a time and was X-ray dosage-dependent. When the adenovirus infection was scheduled at 24 h after irradiation, cancer cells had the lowest viability. Adenovirus and irradiation induced cell death through the caspase-3 related apoptotic pathway, and bladder cancer cells were arrested at the G1 (BIU-87) or S phase (EJ). Autophagic vacuoles were observed in bladder cancer cells treated with radiation and adenovirus. After irradiation, more virus particles were observed in the BIU-87 and EJ cells. However, by a TCID50 assay, there was no difference in virus titter between irradiated bladder cancer cells and unirradiated cells. The proteins Mre11, Chk2-Thr68 which involved in the DNA break repair pathway were decreased while γ-H2AX-Ser139 increased; at the same time, the E1A gene and the hexon proteins of oncolytic adenovirus were increased after irradiation.Conclusions: Our results proved synergistic antitumor effect of adenovirus Ad-PSCAE-UPII-E1A and radiation, which might be a potential therapeutic strategy for bladder cancer.

P8. The in vitro comparison of gold nanoparticles in different cell lines

Introduction Gold nanoparticles (AuNPs) have been recognized as effective radiosensitizers of low energy (e.g. 200–500 kV) X-rays, leading to the emission of Auger electrons that cause highly localized ionizing damage to cells. The aim of this study was to determine possible toxicity caused by AuNPs and to establish whether the AuNPs interacts with MV X-rays. Materials and methods The interaction between the 5 and 10 nm AuNPs with 6 MV X-rays were carried out in different cell lines, namely CHO-K1, BEnd5, MCF-7 and MCF-10A. The X-rays is a low linear energy transfer (LET) radiation type, which was scattered by using a Shonka chamber to obtain lower energies X-rays to interact with the AuNPs. The cells were incubated with 50 μg/ml of the respective AuNPs for 4 h and given a 2 Gy dose. The media was replaced and the cells were incubated for 24 h in the presence of cytochalasin B, then fixed and stained with acridine orange. Results In some of the cell types used in this study, higher MNi frequencies were induced by a combination treatment of radiation and AuNPs compared to the additive sum noted in samples exposed to AuNPs and radiation separately. The AuNPs alone reduced the growth rate of all types between 29% and 33%. Conclusion Interactions between the AuNPs and scattered 6 MV X-rays were noted for CHO-K1 and MCF-7 cells, but not for other cell types used in the study. The cellular uptake for AuNPs needs to be quantified to explain the results.

Abstract 3539: Vitamin D/EB 1089 mediated radio-sensitization of lung cancer cells and head and neck cancer cells

Abstract Lung cancer is a principal factor contributing to cancer-related mortality in the United States. Patients with lung cancer generally have a poor prognosis and resection is often not possible. Our previous work has demonstrated that Vitamin D and its analog, EB1089 (EB), enhance radio sensitivity of H460 and A549 non-small cell lung cancer (NSCLC) cells (Sharma et al; A novel cytostatic form of autophagy in sensitization of non-small cell lung cancer cells to radiation by vitamin D and the vitamin D analog, EB 1089. Autophagy; 2014;10(12):2346-61). In this study, we have extended these findings of Vitamin D/EB 1089 induced radio-sensitization in multiple tumor cell lines such as Lewis Lung mouse non-small cell lung cancer cells (LLC), head and neck cancer cells (HN30) and a primary cell line established from a lung tumor obtained from a cancer patient. All cell lines were treated with multiple doses of radiation in the range of 2-6 Gy and EB1089 was used at concentration of 100nM. Sensitivity was determined based on viable cell number and clonogenic survival. We observed enhanced radiation sensitivity of LLC and HN30 cells with the combination treatment of radiation and EB1089. However, as reported previously by our laboratory (Sharma et al., 2014; Autophagy), sensitization was dependent on the presence of functional p53 and was not evident in HN6 head and neck tumor cells that are mutant in p53. These data suggest that Vitamin D or a Vitamin D analog could be used to enhance radiation sensitivity of various malignancies but only where the tumors express wild type p53. Furthermore, we were able to demonstrate sensitization in a primary cell line established from lung tumor tissues utilizing conditioned medium from stromal cells treated with EB1089. These data suggest that stromal re-programming of cancer cells could influence radiation sensitivity. In studies to define the signaling pathways associated with radiation sensitization, we also observed inactivation by EB 1089 of the NF-kB pathway that was activated by radiation alone in H460 and H1299 NSCLC cells. Silencing of AMPK attenuated radiation sensitization by EB 1089. Sensitization was accompanied by enhanced secretion of the autophagy/senescence related marker, HMGB1. Taken together, these studies indicate that Vitamin and/or its analogs enhance radiosensitivity by cellular pathways involving NF-kB and AMPK and that HMGB1 may be secreted to activate an immune response to the combination treatment. Citation Format: Theresa Thekkudan, Khushboo Sharma, Tareq Saleh, David Gewirtz. Vitamin D/EB 1089 mediated radio-sensitization of lung cancer cells and head and neck cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3539.

Inhibition of Glut1 by WZB117 sensitizes radioresistant breast cancer cells to irradiation.

Breast cancer is the most common type of cancer with high incidence in women. Currently, identifying new therapies that selectively inhibit tumor growth without damaging normal tissue are a major challenge of cancer research. One of the features of cancer cells is that they do not consume more oxygen even under normal oxygen circumstances but prefer to aerobic glycolysis through the enhanced catabolism of glucose and glutamine. In this study, we investigate the mechanisms of the radioresistance in breast cancer cells. Human breast cancer cells MDA-MB-231 and MCF-7 were treated with radiation alone, Glut1 inhibitor alone or the combination of both to evaluate cell glucose metabolism and apoptosis. By the establishment of radioresistant cell line, we investigate the mechanisms of the combined treatments of radiation with Glut1 inhibitor in the radioresistant cells. The glucose metabolism and the expression of Glut1 are significantly stimulated by radiotherapy. We report the radioresistant breast cancer cells exhibit upregulated Glut1 expression and glucose metabolism. In addition, we observed overexpression of Glut1 renders breast cancer cells resistant to radiation and knocking down of Glut1 sensitizes breast cancer cells to radiation. We treated breast cancer cells with radiation and WZB117 which inhibits Glut1 expression and glucose metabolism and found the combination of WZB117 and radiation exhibits synergistically inhibitory effects on breast cancer cells. Finally, we demonstrate the inhibition of Glut1 re-sensitizes the radioresistant cancer cells to radiation. This study reveals the roles of Glut1 in the radiosensitivity of human breast cancer. It will provide new mechanisms and strategies for the sensitization of cancer cells to radiotherapy through regulation of glucose metabolism.

NSCLC cells demonstrate differential mode of cell death in response to the combined treatment of radiation and a DNA-PKcs inhibitor.

The current standard of care for lung cancer consists of concurrent chemotherapy and radiation. Several studies have shown that the DNA-PKcs inhibitor NU7441 is a highly potent radiosensitizer, however, the mechanism of NU7441's anti-proliferation effect has not been fully elucidated. In this study, the combined effect of NU7441 and ionizing radiation (IR) in a panel of non-small cell lung cancer cell lines (A549, H460 and H1299) has been investigated. We found that NU7441 significantly enhances the effect of IR in all cell lines. The notable findings in response to this combined treatment are (i) prolonged delay in IR-induced DNA DSB repair, (ii) induced robust G2/M checkpoint, (iii) increased aberrant mitosis followed by mitotic catastrophe specifically in H1299, (iv) dramatically induced autophagy in A549 and (v) IR-induced senescence specifically in H460. H1299 cells show greater G2 checkpoint adaptation after combined treatment, which can be attributed to higher expression level of Plk1 compared to A549 and H460. The enhanced autophagy after NU7441 treatment in A549 is possibly due to the higher endogenous expression of pS6K compared to H1299 and H460 cells. In conclusion, choice of cell death pathway is dependent on the mutation status and other genetic factors of the cells treated.

Addition of anti-neu antibody to local irradiation can improve tumor-bearing BALB/c mouse survival through immune-mediated mechanisms.

This study investigated the therapeutic effects of combined local irradiation and anti-HER2/neu antibody in a mixed tumor mouse model comprised of a nonmetastatic neu-positive tumor and a metastatic neu-negative tumor. While local irradiation alone could control the primary tumor in a dose-dependent manner, it did not improve mouse survival. Combined treatment comprised of local irradiation and anti-neu antibody of tumor-bearing BALB/c mice significantly improved mouse survival (P < 0.5), even though the tumor growth was similar to that of the irradiated-alone group. The combined treatment significantly reduced metastatic tumor masses in the lung and increased immune cell infiltration in primary tumor tissues. However, immune deficient nude mice with tumors did not exhibit prolonged survival in response to the combined treatment. Collectively, these results show that combined local irradiation and anti-neu antibody can elicit an immune-mediated abscopal effect to extend survival. Although the mechanism for abscopal effects induced by the combined treatment of radiation and anti-HER2/neu antibody was not elucidated, to our knowledge this is the first published study to describe the abscopal effect induced by the combination of local irradiation and the anti-HER2/neu antibody.

Double-blind, randomized pilot study of bioadhesive chlorhexidine gel in the prevention and treatment of mucositis induced by chemoradiotherapy of head and neck cancer.

BackgroundTo evaluate, in an initial way, the effectiveness of bioadhesive chlorhexidine gel 0.2% versus placebo as a preventive and therapeutic intervention of oral mucositis induced by radiation therapy and chemotherapy in patients diagnosed with head and neck cancer treated with chemoradiotherapy.Material and MethodsIn this pilot study, 7 patients (range of age: 18- 65), having histological documented diagnosis of squamous carcinoma on the head and neck region in stage III and IV, and receiving combined radiation treatment and chemotherapy (cisplatin 100 mg/m2 IV on days 1, 22, and 43 of irradiation) were studied. Simultaneously, a topical application was performed with bioadhesive chlorhexidine gel 0.2% in the study group, and the placebo gel for the control group in 5 applications per day, from the time of initiation of cancer treatment to 2 weeks after completion of chemo-radiotherapy treatment (11 weeks of follow-up). The gradation of mucositis, pain, analgesic consumption, infectious complications, and treatment tolerance was measured.ResultsAfter 7 patients completed the protocol, any differences were observed between groups in an interval analysis. Mucositis, pain, and tolerance was similar in both groups.ConclusionsOur results must be interpreted with caution due to the reduced sample size, but the use of bioadhesive chlorhexidine gel 0.2% didn’t contribute clinical improvement to the oral mucositis induced by radiation therapy and chemotherapy. Key words: Chlorhexidine, mucositis, head and neck cancer.

Hypoxia-induced autophagy contributes to radioresistance via c-Jun-mediated Beclin1 expression in lung cancer cells.

Reduced radiosensitivity of lung cancer cells represents a pivotal obstacle in clinical oncology. The hypoxia-inducible factor (HIF)-1α plays a crucial role in radiosensitivity, but the detailed mechanisms remain elusive. A relationship has been suggested to exist between hypoxia and autophagy recently. In the current study, we studied the effect of hypoxia-induced autophagy on radioresistance in lung cancer cell lines. A549 and H1299 cells were cultured under normoxia or hypoxia, followed by irradiation at dosage ranging from 0 to 8 Gy. Clonogenic assay was performed to calculate surviving fraction. EGFP-LC3 plasmid was stably transfected into cells to monitor autophagic processes. Western blotting was used to evaluate the protein expression levels of HIF-1α, c-Jun, phosphorylated c-Jun, Beclin 1, LC3 and p62. The mRNA levels of Beclin 1 were detected by qRT-PCR. We found that under hypoxia, both A549 and H1299 cells were radio-resistant compared with normoxia. Hypoxia-induced elevated HIF-1α protein expression preferentially triggered autophagy, accompanied by LC3 induction, EGFP-LC3 puncta and p62 degradation. In the meantime, HIF-1α increased downstream c-Jun phosphorylation, which in turn upregulated Beclin 1 mRNA and protein expression. The upregulation of Beclin 1 expression, instead of HIF-1α, could be blocked by SP600125 (a specific inhibitor of c-Jun NH2-terminal kinase), followed by suppression of autophagy. Under hypoxia, combined treatment of irradiation and chloroquine (a potent autophagy inhibitor) significantly decreased the survival potential of lung cancer cells in vitro and in vivo. In conclusion, hypoxia-induced autophagy through evaluating Beclin1 expression may be considered as a target to reverse the radioresistance in cancer cells.

Abstract 4903: Luteolin's role as a radiosensitizer by promoting cell death and ROS modulation

Abstract Radiotherapy is one of major cancer treatment, but radiation treatment could evoke resistance or side effects such as fibrosis. To overcome these obstacles against radiation treatment, many researchers are developing effective radiosensitizer. To develop a new radiosensitizer, we test whether luteolin has functions as a radiosensitizer candidate because previous studies already demonstrated luteolin could promote cancer cell death by reactive oxygen species (ROS) induction, and this phenomenon is one of main effects of radiation-induced cell death. Luteolin is 3′,4′,5,7-tetrahydroxyflavone, which could induce cell death of various cancer cells. We observed luteolin treatment could induce cell death of non-small cell lung cancer cells with independent manner of p53 and PTEN status, and combination treatment of radiation and luteolin enhance more cell death than those of radiation only or luteolin only treatment condition. Dose enhancement ratios of luteolin and radiation combination are 1.54 and 1.31 in NCI-H460 and NCI-H1299, respectively. Combined treatment with luteolin and radiation down-regulate Bcl-2 level and induce the phosphorylation of JNK and activation of caspase-3/9. ROS accumulation also was induced in combined condition of luteolin and radiations. In a xenograft assay, the combined luteolin and radiation group showed 27.2 days of growth delay versus the control in terms of tumor growth. The enhancement factor of this combined treatment was determined to be 3.2. Taken together, we conclude that luteolin contain role of radiosensitizer via promotion of cell death and ROS accumulation. Citation Format: Kwang-Chul Ahn, Jae Yeon Choi, Sang-Gu Hwang, Hong-Duck Um, Jong Kuk Park. Luteolin's role as a radiosensitizer by promoting cell death and ROS modulation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4903. doi:10.1158/1538-7445.AM2014-4903

Abstract 4911: NSCLC cells demonstrate differential mode of cell death in response to the combined treatment of radiation and a DNA-PKcs inhibitor

Abstract Introduction: Lung cancers demonstrate the highest number of p53 mutations of any cancer with 70% of small cell lung cancers and 33% of adenocarcinomas containing a mutation. Loss of p53 function has been correlated with therapeutic resistance and poor clinical outcomes. Therefore, developing therapeutic strategies that specifically target p53 loss-of-function mutants is of the utmost importance. The purpose of this investigation is to explore whether p53 status has impact on the radio-sensitizing effect of a DNA-PKcs inhibitor (NU7441). Methods: Clonogenic surviving fraction analysis, DNA double strand break repair kinetics, cell cycle analysis, immunofluorescence, immunoblot, apoptosis and autophagy assays were used to investigate the mechanism of radiosensitization of NU7441 in NSCLC cell lines (A549, H1299, and H460) with differential levels of p53 expression. Results: NU7441 substantially inhibited the repair of IR-induced DNA double strand break (DSB) in all three cell lines. Clonogenic surviving fraction analysis reveals that NU7441 is a better radio-sensitizer in p53-deficient cells (H1299) when compared to p53-wild type cells (A549, H460). Combination of ionizing radiation (IR) and NU7441 leads to a more robust G2 arrest in A549 and H460 cells when compared to radiation treatment only. However, NU7441 and radiation preferentially induced mitotic arrest in H1299 consequently leading to a significant increase in mitotic catastrophe. Furthermore, NU7441 led to an increase in apoptosis rather than autophagy as the predominant cell death pathway in p53-deficient cells. Moreover, knockdown of p53 using siRNA sensitized A549 to NU7441+IR treatment. Conclusion: Our study clearly shows that NU7441, a novel DNA-PKcs inhibitor, is a potent radio-sensitizer in p53-dificient lung cancer cells and highlights the promise of NU7441 in targeted cancer treatment. Citation Format: Yu Lan, Zengfu Shang, Feng-Ming Hsu, Vasu Tumati, Benjamin P. Chen, Debabrata Saha. NSCLC cells demonstrate differential mode of cell death in response to the combined treatment of radiation and a DNA-PKcs inhibitor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4911. doi:10.1158/1538-7445.AM2014-4911

Abstract 2067: Hyperpolarized 13C-pyruvate MRS quantitatively monitor the therapeutic efficacy of adjuvant metformin combined RT in brain metastasis from triple negative breast cancer

Abstract Introduction The hyperpolarized 13C-pyruvate is a robust imaging biomarker to evaluate the metabolic status of cancer to monitor the anti-cancer therapeutic effect and to predict the prognosis as earliest as possible by 10,000 fold increase of MRS sensitivity. According to the clinical epidemiological research, metformin reduces cancer incidence or mortality in type II diabetes patients. In this study, we investigated the anti-cancer metabolic effect of metformin as an adjuvant for the radiation therapy to treat brain metastasis from triple negative breast cancer in nude mouse model by measuring the metabolic flux through the hyperpolarized 13C-pyruvate MRS. Methods Six weeks old BALB/C nude mice were stereotactically implanted 2×105 MDA-MB-231-luciferase breast cancer cells in the striatum of brain. After 1 week from tumor implantation, animals were randomly divided into 4 groups: vehicle (distilled water), oral metformin alone (MET), radiation treatment (RT), and radiation combined with adjuvant oral metformin treatment (METRT). Mice were treated with 300 mg/kg of oral metformin for 5 days in a week from week 1 until when the animals die. MRI and 13C MRS was performed at week 2 and week 3, before and after treatment. Brain tumors were irradiated at week 2 with 3Gy for 5 consecutive days. MRI and MRS was performed at 9.4T Bruker MRI scanner using 20mm surface dual tuned 1H-13C coil. 75mmole of hyperpolarized [1-13C] pyruvate was injected via tail vein in all mice. Metabolic flux was calculated as lactate/pyruvate ratio. The progression and the response to treatment was also monitored by bioluminescence imaging. Paraffin sections were stained with H&amp;E for histological evaluation. Results There was no difference in tumor growth and metabolic flux rate between vehicle and MET alone groups. Vehicle group showed 260% increase in tumor mass, whereas RT group showed only 39% increase in tumor volume. 13C MRS showed 60% decrease in lactate/pyruvate flux ratio in RT group, whereas vehicle group showed 60% increase in metabolic flux ratio. Interestingly, the tumor volume was significantly regressed and 13C-lactate flux was significantly decreased in METRT group after treatment. Bioluminescence imaging showed time-dependent increasing flux in vehicle group, but RT and METRT groups showed decreased photon flux activity. In comparison of METRT with RT alone group, bioluminescence activity was significantly decreased in METRT group. H&amp;E staining of histological sections showed significant tumor necrosis and decreased cellularity in METRT group. Conclusion Hyperpolarized 13C-pyruvate MRS informs the adjuvant therapeutic effect of metformin and RT in brain metastasis from triple negative breast cancer. Citation Format: Young-suk Choi, Han-Sol Lee, Jung-Sung Lee, Hyun-Jin Park, Ju-Hyun Lee, Eun-Kyung Wang, Seung-Wook Yang, Eunhae Joe, Soo Hyeon Lee, Dong-Hyun Kim, Ho-Taek Song. Hyperpolarized 13C-pyruvate MRS quantitatively monitor the therapeutic efficacy of adjuvant metformin combined RT in brain metastasis from triple negative breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2067. doi:10.1158/1538-7445.AM2014-2067

Considerations for combined immune checkpoint modulation and radiation treatment.

Recent advances indicate that new therapeutic strategies for the treatment of malignancies will be realized from combined radiation treatment and immune checkpoint modulation. Numerous biophysical properties must be considered for effective biologic development, including affinity, selectivity, oligomeric state and valency. High-resolution structural characterization contributes to our understanding of these properties and can lead to the realization of proteins with unique in vitro activities and novel in vivo therapeutic functions. In this article we focus on the importance of these factors for new potential biologics and consider these in the context of combination therapies with physical modalities, including radiation therapy. In particular, we examine the consequences of altered avidities and subset-specific ligand density on the rational modification of biological function in the immunoglobulin and tumor necrosis factor superfamilies and for new optimized combination therapies.

Real-world cost-effectiveness of cetuximab in locally advanced squamous cell carcinoma of the head and neck.

Clinical trial EMR 62202-006 demonstrates prolonged median locoregional control (24.4 vs. 14.9 months), progression-free survival (17.1 vs. 12.4 months) and overall survival (49.0 vs. 29.3 months) for patients who receive cetuximab added to the comparator radiotherapy for locally advanced squamous cell carcinoma of the head and neck (LA SCCHN). In the Netherlands, hospitals receive reimbursement for cetuximab conditional on cost-effectiveness in daily practice. To estimate the real-world incremental cost per quality adjusted life-year (QALY) gained for radiotherapy + cetuximab over radiotherapy alone in first line treatment of LA SCCHN, a Markov model is constructed with health states "alive without progression", "alive following progression" and "death". Transition probabilities per month are estimated from clinical trial data and retrospectively collected real-world data from two Dutch head and neck cancer treatment centres (2007-2010, n = 141). 5-year, 10-year and lifetime horizons are used, without and with discounting (4 % costs, 1.5 % effects) to calculate incremental cost-effectiveness ratios. Two scenarios explore different assumptions on prognosis of real-world versus trial patients. Adding cetuximab to radiotherapy results in increased costs and health gains in both scenarios and across each of the time horizons. Incremental costs per QALY gained range between <euro>14,624 and <euro>38,543 in the base-case. For a willingness to pay of <euro>80,000 per QALY, the acceptability curves for the different scenarios show probabilities between 0.76 and 0.87 of radiotherapy + cetuximab being cost-effective compared to radiotherapy alone. Current results show the combined treatment of radiotherapy + cetuximab to be a cost-effective treatment option for patients with LA SCCHN.

Gene expression changes after ionizing radiation in endothelial cells derived from human endometrial cancer-preliminary outcomes

Accumulating evidence has demonstrated that death of microvascular endothelial cells plays a decisive role in the tumor response against radiotherapy. Nevertheless, radiation-induced gene alterations on cancer-associated endothelial cells of human endometrial carcinoma remain poorly understood. The purpose of this study was to elucidate the gene expression changes after X-ray radiation in human endometrial carcinoma vascular endothelial cells and to provide new targets for combined treatment of radiation and anti-angiogenesis in human endometrial carcinoma. Endometrial cancer-derived endothelial cells, which obtained before and 4 h after 400 cGy X-ray radiation from four endometrial carcinomas, were analyzed by gene expression profile. The selected meaningful genes from gene microarray experiments were validated by real-time quantitative PCR. Microarray analyses showed 49 significantly changed genes which were common to all the microarray experiments. There into, 14 genes were found to be in persistent up-regulation and 14 in persistent down-regulation 4 h after X-ray radiation when compared with the control group. These genes were involved in cell cycle and growth regulation, cell-apoptosis, chemokine, cell signaling, cellular stress response, angiogenesis, DNA synthesis and repair and cell adhesion. Eight randomly selected genes were validated by real-time PCR. The genes of cancer-derived endothelial cells regulated by X-ray radiation as well as their related signal pathways, which obtained from gene expression profiling data, were relevant to radiosensitivity of endometrial cancer. This study shows that the identified genes and their related signaling pathways are candidated biomarkers for radiation and anti-angiogenesis of human endometrial carcinoma.

In vitro evaluation of photon and raster-scanned carbon ion radiotherapy in combination with gemcitabine in pancreatic cancer cell lines

Background: Pancreatic cancer is the fourth leading cause of cancer deaths, being responsible for 6% of all cancer-related deaths. Conventional radiotherapy with or without additional chemotherapy has been applied in the past in the context of neoadjuvant or adjuvant therapy concepts with only modest results, however new radiation modalities, such as particle therapy with promising physical and biological characteristics, present an alternative treatment option for patients with pancreatic cancer. Up until now the raster scanning technique employed at our institution for the application of carbon ions has been unique, and no radiobiological data using pancreatic cancer cells has been available yet. The aim of this study was to evaluate cytotoxic effects that can be achieved by treating pancreatic cancer cell lines with combinations of X-rays and gemcitabine, or alternatively with carbon ion irradiation and gemcitabine, respectively. Materials and Methods: Human pancreatic cancer cell lines AsPC-1, BxPC-3 and Panc-1 were irradiated with photons and carbon ions at various doses and treated with gemcitabine. Photon irradiation was applied with a biological cabin X-ray irradiator, and carbon ion irradiation was applied with an extended Bragg peak (linear energy transfer (LET) 103 keV/μm) using the raster scanning technique at the Heidelberg Ion Therapy Center (HIT). Responsiveness of pancreatic cancer cells to the treatment was measured by clonogenic survival. Clonogenic survival curves were then compared to predicted curves that were calculated employing the local effect model (LEM). Results: Cell survival curves were calculated from the surviving fractions of each combination experiment and compared to a drug control that was only irradiated with X-rays or carbon ions, without application of gemcitabine. In terms of cytotoxicity, additive effects were achieved for the cell lines Panc-1 and BxPC-3, and a slight radiosensitizing effect was observed for AsPC-1. Relative biological effectiveness (RBE) of carbon ion irradiation ranged from 1.5–4.5 depending on survival level and dose. Sensitizer enhancement ratio (SER) values calculated at 10% cell survival ranged from 1.24–1.66, depending on cell line, gemcitabine dose and irradiation modality. Experimentally ascertained survival curves matched those predicted by LEM-calculation. Conclusion: Our experiments have shown a combined treatment of irradiation and chemotherapy with gemcitabine to be a good means of achieving additive cytotoxic effects on pancreatic cancer cell lines. The data generated in this study will serve as radiobiological basis for further preclinical and clinical studies.