Anginex synergizes with radiation therapy to inhibit tumor growth by radiosensitizing endothelial cells

We have demonstrated that the designed peptide anginex displays potent antiangiogenic activity. The aim of our study was to investigate the effect of anginex on established tumor vasculature as an adjuvant to radiation therapy of solid tumors. In the MA148 human ovarian carcinoma athymic mouse model, anginex (10 mg/kg) in combination with a suboptimal dose of radiation (5 Gy once weekly for 4 weeks) caused tumors to regress to an impalpable state. In the more aggressive SCK murine mammary carcinoma model, combination of anginex and a single radiation dose of 25 Gy synergistically increased the delay in tumor growth compared to the tumor growth delay caused by either treatment alone. Immunohistochemical analysis also demonstrated significantly enhanced effects of combined treatment on tumor microvessel density and tumor or endothelial cell proliferation and viability. In assessing physiologic effects of anginex, we observed a reduction in tumor perfusion and tumor oxygenation in SCK tumors after 5-7 daily treatments with anginex with no reduction in blood pressure. To test anginex as a radiosensitizer, additional studies using SCK tumors were performed. Three daily i.p. injections of anginex were able to enhance the effect of 2 radiation doses of 10 Gy, resulting in 50% complete responses, whereas the known antiangiogenic agent angiostatin did not enhance the radiation response of SCK tumors. Mechanistically, it appears that anginex functions as an endothelial cell-specific radiosensitizer because anginex showed no effect on in vitro radiosensitivity of SCK or MA148 tumor cells, whereas anginex significantly enhanced the in vitro radiosensitivity of 2 endothelial cell types. This work supports the idea that the combination of the antiangiogenic agent anginex and radiation may lead to improved clinical outcome in treating cancer patients.     

Response of intracerebral human glioblastoma xenografts to multifraction radiation exposures

PURPOSE: We investigated the effects of fractionated radiation treatments on the life spans of athymic rats bearing intracerebral brain tumors. METHODS AND MATERIALS: U-251 MG or U-87 MG human glioblastoma cells were implanted into the brains of athymic rats, and the resulting tumors were irradiated once daily with various doses of ionizing radiation for 5 consecutive days or for 10 days with a 2-day break after Day 5. RESULTS: Five daily doses of 1 and 1.5 Gy, and 10 doses of 0.75 and 1 Gy, cured some U-251 MG tumors. However, five daily doses of 0.5 Gy increased the survival time of animals bearing U-251 MG tumors 5 days without curing any animals of their tumors. Ten doses of 0.3 Gy given over 2 weeks extended the lifespan of the host animals 9 days without curing any animals. For U-87 MG tumors, 5 daily doses of 3 Gy produced an increased lifespan of 8 days without curing any animals, and 10 doses of 1 Gy prolonged lifespan 5.5 days without curing any animals. The differences in extension of life span between the 5- and 10-fraction protocols were minor for either tumor type. CONCLUSION: The finding that the U-251 MG tumors are more sensitive than U-87 MG tumors, despite the fact that U-251 MG tumors contain many more hypoxic cells than U-87 MG tumors, suggests the intrinsic cellular radiosensitivities of these cell lines are more important than hypoxia in determining their in vivo radiosensitivities.     

Hyperthermia enhancement of radiation response and inhibition of recovery from radiation damage in human glioma cells

Three human glioma cell lines were tested for the effectiveness of hyperthermia and thermal radiosensitization. Thermal sensitization was evaluated from the perspective of increased radiosensitivity as well as inhibition of recovery from radiation damage. The three glioma cell lines tested showed large shoulders on the radiation survival curve and a large capacity for recovery of potentially lethal radiation damage. Hyperthermia caused radiosensitization in all three cell lines, which was primarily characterized by the reduction of the survival curve shoulder with moderate decreases in the survival curve slope. The radiosensitization was dependent on the time and temperature of the hyperthermia treatment. At 45°C for 60 min the shoulder of the radiation survival curve could be completely eliminated and the degree of enhanced cell killing at the 2 Gy level ranged from factors of 10 to 20 under the various conditions. When hyperthermia was given to cells which were irradiated and then plated immediately, or delayed for 8 h before plating to allow recovery, hyperthermia was found to cause radiosensitization under both conditions. In addition, when the hyperthermia dose was increased the difference between the immediate plating and the delayed plating survival curve decreased and for 45°C for 60 min this difference was completely eliminated, concomitantly with the elimination of the survival curve shoulder. These data indicate that hyperthermia may play a role in radiosensitization for the treatment of human glioma.     

Porfimer-sodium (Photofrin-II) in combination with ionizing radiation inhibits tumor-initiating cell proliferation and improves glioblastoma treatment efficacy

Tumor relapse and tumor cell repopulation has been explained partially by the drug-free break period between successive conventional treatments. Strategies to overcome tumor relapse have been proposed, such as the use of chemotherapeutic drugs or radiation in small, frequent fractionated doses without an extended break period between treatment intervals. Yet, tumors usually acquire resistance and eventually escape the therapy. Several mechanisms have been proposed to explain the resistance of tumors to therapy, one of which involves the cancer stem cell or tumor-initiating cell (TIC) concept. TICs are believed to resist many conventional therapies, in part due to their slow proliferation and self-renewal capacities. Therefore, emerging efforts to eradicate TICs are being undertaken. Here we show that treatment with Photofrin II, among the most frequently used photosensitizers, sensitized a TIC-enriched U-87MG human glioblastoma cell to radiation, and improve treatment outcome when used in combination with radiotherapy. A U-87MG tumor cell population enriched with radiation-resistant TICs becomes radio-sensitive, and an inhibition of cell proliferation and an increase in apoptosis are found in the presence of Photofrin II. Furthermore, U-87MG tumors implanted in mice treated with Photofrin II and radiation exhibit a significant reduction in angiogenesis and vasculogenesis, and an increased percentage of apoptotic TICs when compared with tumors grown in mice treated with radiation alone. Collectively, our results offer a new possible explanation for the therapeutic effects of radiosensitizing agents, and suggest that combinatorial treatment modalities can effectively prolong treatment outcome of glioblastoma tumors by inhibiting tumor growth mediated by TICs.     

Real-life activity of eribulin mesylate among metastatic breast cancer patients in the multicenter national observational ESME program

Eribulin mesylate (EM) was recently approved for metastatic breast cancer (MBC) chemotherapy (CT) in late lines by the FDA, with debated results in second line. We evaluated outcomes in breast cancer patients receiving EM as second, third and fourth line in a national real-life cohort of 16,703 consecutive MBC patients initiating their first metastatic therapeutic line between 2008 and 2014. Primary and secondary objectives were overall survival (OS) and progression-free survival (PFS). An imbalance was seen for HER2+ tumors and concomitant anti-HER2 targeted therapies use, we thus performed a subanalysis in HER2− patients. PFS and OS were significantly better in EM patients in third and fourth lines, compared to “Other chemotherapies” patients (PFS: 4.14 vs. 3.02 months, p = 0.0010; 3.61 vs. 2.53 months, p = 0.0102, third and fourth-line; OS: 11.27 vs. 7.65 months, p = 0.0001; 10.91 vs. 5.95 months, p < 0.0001, third and fourth-line). No significant difference was reported in second-line (PFS: 5.06 vs. 4.14 months, p = 0.1171; OS: 13.99 vs. 11.66 months, p = 0.151). Among HER2− patients, a significant difference was seen for all lines, including 2nd-line (PFS: 4.57 vs. 3.91 months, p = 0.0379; OS: 14.98 vs. 10.51 months, p = 0.0113). In this large real-world database, HER2-negative MBC patients receiving EM in second or later CT line presented significantly better PFS and OS. This difference disappeared in second line in the overall population, probably because of the imbalance in HER2-targeted treatments use. Our results mirror those of the published randomized trials. The effect of anti-HER2 therapies addition in this setting still needs to be defined.     

Phase I study of the halichondrin B analogue eribulin mesylate in combination with cisplatin in advanced solid tumors

Background:

Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.

Methods:

Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7–1.4 mg m⁻² and CP 60–75 mg m⁻². Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m⁻², CP 60 mg m⁻²) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.

Results:

On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m⁻², 60 mg m⁻²); G 3 anorexia/fatigue/hypokalemia (1.2 mg m⁻², 60 mg m⁻²); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m⁻², 60 mg m⁻²). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m⁻², 60 mg m⁻²); G 4 mucositis (1.4 mg m⁻², 60 mg m⁻²); and G 3 hypokalemia (1.2 mg m⁻², 75 mg m⁻²). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m⁻² (days 1, 8) and CP 75 mg m⁻² (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).

Conclusions:

On the 21-day cycle, eribulin mesylate 1.2 mg m⁻², administered on days 1 and 8, in combination with CP 75 mg m⁻², administered on day 1 is well tolerated and showed preliminary anticancer activity.     

Prolonged survival for patients with newly diagnosed, inoperable glioblastoma with 3-times daily ultrafractionated radiation therapy

Ultrafractionation of radiation therapy is a novel regimen consisting of irradiating tumors several times daily, delivering low doses (<0.75 Gy) at which hyperradiosensitivity occurs. We recently demonstrated the high efficiency of ultrafractionated radiotherapy (RT) on glioma xenografts and report here on a phase II clinical trial to determine the safety, tolerability, and efficacy of an ultrafractionation regimen in patients with newly and inoperable glioblastoma (GBM). Thirty-one patients with histologically proven, newly diagnosed, and unresectable supratentorial GBM (WHO grade IV) were enrolled. Three daily doses of 0.75 Gy were delivered at least 4 hours apart, 5 days per week over 6–7 consecutive weeks (90 fractions for a total of 67.5 Gy). Conformal irradiation included the tumor bulk with a margin of 2.5 cm. The primary end points were safety, toxicity, and tolerability, and the secondary end points were overall survival (OS) and progression-free survival (PFS). Multivariate analysis was used to compare the OS and PFS with the EORTC-NCIC trial 26981-22981/CE.3 of RT alone vs radiation therapy and temozolomide (TMZ). The ultrafractionation radiation regimen was safe and well tolerated. No acute Grade III and/or IV CNS toxicity was observed. Median PFS and OS from initial diagnosis were 5.1 and 9.5 months, respectively. When comparing with the EORTC/NCIC trial, in both PFS and OS multivariate analysis, ultrafractionation showed superiority over RT alone, but not over RT and TMZ. The ultrafractionation regimen is safe and may prolong the survival of patients with GBM. Further investigation is warranted and a trial associating ultra-fractionation and TMZ is ongoing.     

Effect of VEGF receptor inhibitor PTK787/ZK222584 [correction of ZK222548] combined with ionizing radiation on endothelial cells and tumour growth.

The vascular endothelial growth factor (VEGF) receptor is a major target for anti-angiogenesis-based cancer treatment. Here we report the treatment effect of ionizing radiation in combination with the novel orally bioavailable VEGF receptor tyrosine kinase inhibitor PTK787/ZK222584 on endothelial cell proliferation in vitro and with tumour xenografts in vivo. Combined treatment of human umbilical vein endothelial cells with increasing doses of PTK787/ZK222584 and ionizing radiation abrogated VEGF-dependent proliferation in a dose-dependent way, but inhibition of endothelial cell proliferation was not due to apoptosis induction. In vivo, a combined treatment regimen of PTK787/ZK222584 (4 x 100 mg/kg) during 4 consecutive days in combination with ionizing radiation (4 x 3 Gy) exerted a substantial tumour growth delay for radiation-resistant p53-dysfunctional tumour xenografts derived from SW480 colon adenocarcinoma cells while each treatment modality alone had only a minimal effect on tumour size and neovascularization. SW480 tumours from animals that received a combined treatment regimen, displayed not only an extended tumour growth delay but also a significant decrease in the number of microvessels in the tumour xenograft. These results support the model of a cooperative anti-tumoral effect of angiogenesis inhibitor and irradiation and show that the orally bioavailable VEGF receptor tyrosine kinase inhibitor PTK787/ZK222584 is suitable for combination therapy with irradiation.     

亚砷酸联合电离辐射作用于肝癌细胞株 HepG2 的实验观察

目的：探讨亚砷酸对肝癌细胞株HepG2的放疗增敏作用.方法：采用细胞培养及传代方法,加入不同浓度亚砷酸,48h后用四唑盐实验（MTT）法检测肝癌细胞株HepG2的抑制率.不同剂量6兆伏X射线照射肝癌细胞株,48h后用平板克隆形成实验观察存活分数.结果：在一定浓度范围内（1.25-10mg/ml）,亚砷酸对HepG2细胞增殖的抑制呈浓度依赖性;亚砷酸联合放疗能降低HepG2细胞存活分数,可以使细胞存活曲线的D0值从单纯放疗组的1.94降至1.75,放射增敏比为1.38.结论：亚砷酸对肝癌细胞株HepG2具有放疗增敏作用.     

低剂量辐射对Lewis肺癌小鼠肿瘤微环境的影响

目的 探讨低剂量辐射(LDR)对Lewis肺癌小鼠肿瘤微环境(TME)的影响,以及高剂量辐射(HDR)前LDR预处理在TME中发挥的效应机制.方法 接种Lewis肺癌细胞(1×106)于雄性C57BL/6小鼠左侧腋下,待小鼠肿瘤直径1 cm左右(12 d),随机分为假手术Sham(1)组、LDR(2)组、HDR(3)组...     

Thoracic radiation therapy improves the overall survival of patients with extensive-stage small cell lung cancer with distant metastasis

BACKGROUND:

The authors conducted a retrospective study to evaluate the effects of thoracic radiation therapy (TRT) for patients with extensive‐stage small cell lung cancer (ED‐SCLC).

METHODS:

Between January 2003 and December 2006, the records of 119 patients who were diagnosed with ED‐SCLC (all with distant metastasis [M1]) were included in the study. Sixty patients received chemotherapy (ChT) and TRT (ChT/TRT), and 59 patients received ChT alone. The ChT regimens consisted of either carboplatin and etoposide (CE) or cisplatin and etoposide (PE). The total dose of TRT ranged from 40 to 60 grays (Gy) at 1.8 to 2.0 Gy per fraction.

RESULTS:

For the entire group, the median survival was 13 months, and the 2‐year and 5‐year overall survival (OS) rates were 26.1% and 6.5%, respectively. The median survival and the 2‐year and 5‐year OS rates were 17 months, 35%, and 7.1%, respectively, in the ChT/TRT group and 9.3 months, 17%, and 5.1%, respectively, in the ChT group (P = .014). However, this improvement was achieved at the expense of low toxicity. Multivariate analysis revealed that receiving ≥4 cycles of ChT (P = .032) and TRT (P = .005) were favorable prognostic factors for OS. Of all toxicities, only high‐grade leucopenia (grade >3) was more frequent in the ChT/TRT group.

CONCLUSIONS:

The addition of TRT to ChT improved the OS of patients with ED‐SCLC. Furthermore, receiving ≥4 cycles of ChT and TRT were independent, favorable prognostic factors for OS. Cancer 2011;. © 2011 American Cancer Society.     

Esomeprazole enhances the effect of ionizing radiation to improve tumor control

The resistance of cancer cells to radiation-based treatment is a major clinical challenge confounding standard of care in cancer. This problem is particularly notable in many solid tumors where cancer cells are only partially responsive to radiation therapy. Combination of radiation with radiosensitizers is able to enhance tumor cell killing. However, currently available radiosensitizers are associated with significant normal tissue toxicity. Accordingly, there is an unmet need to develop safer and more effective radiosensitizers to improve tumor control. Here, we evaluated the radiosensitizing effect of the FDA-approved drug esomeprazole in normal and radioresistant human head and neck squamous cell carcinoma (HNSCC) cells in vitro, and in a mouse model of HNSCC. For the in vitro studies, we used cancer cell colony formation (clonogenicity) assay to compare cancer cell growth in the absence or presence of esomeprazole. To determine mechanism(s) of action, we assessed cell proliferation and profiled cell cycle regulatory proteins. In addition, we performed reverse phase protein array (RPPA) study to understand the global effect of esomeprazole on over 200 cancer-related proteins. For the in vivo study, we engrafted HNSCC in a mouse model and compared tumor growth in animals treated with radiation, esomeprazole, and combination of radiation with esomeprazole. We found that esomeprazole inhibits tumor growth and dose-dependently enhances the cell killing effect of ionizing radiation in wildtype and p53-mutant radioresistant cancer cells. Mechanistic studies demonstrate that esomeprazole arrests cancer cells in the G1 phase of the cell cycle through upregulation of p21 protein and inhibition of cyclin-dependent kinases (Cdks) type 1 (Cdk1) and type 2 (Cdk2). In vivo data showed greater tumor control in animals treated with combination of radiation and esomeprazole compared to either treatment alone, and that this was associated with inhibition of cell proliferation in vivo. In addition, combination of esomeprazole with radiation significantly impaired repair following radiation-induced DNA damage. Our studies indicate that esomeprazole sensitizes cancer cells to ionizing radiation, and is associated with upregulation of p21 to arrest cells in the G1 phase of the cell cycle. Our findings have significant therapeutic implications for the repurposing of esomeprazole as a radiosensitizer in HNSCC and other solid tumors.     

Experimental anti-angiogenesis causes upregulation of genes associated with poor survival in glioblastoma

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with classic chemotherapy. Exploring gene regulation in tumor cells during anti-angiogenesis might help to comprehend the molecular basis of response to treatment. To generate a defined anti-angiogenic condition in vivo, we transfected human glioma cells with short-interfering RNAs against VEGF-A and implanted them on the chick chorio-allantoic membrane. Gene regulation in avascular tumors was studied using human Affymetrixtrade mark GeneChips. Potentially important genes were further studied in glioma patients. Despite strong VEGF inhibition, we observed recurrent formation of small, avascular tumors. CHI3L2, IL1B, PI3/elafin and CHI3L1, which encodes for YKL-40, a putative prognosticator for various diseases, including cancer, were strongly up-regulated in avascular glioma. In glioblastoma patients, these genes showed coregulation and their expression differed significantly from low-grade glioma. Importantly, high levels of CHI3L1 (p = 0.036) and PI3/elafin mRNA (p = 0.0004) were significantly correlated with poor survival. Cox regression analysis further confirmed that PI3 and CHI3L1 levels are survival markers independent from patient age and sex. Elafin-positive tumor cells were only found in glioblastoma, where they were clustered around necrotic areas. PI3/elafin is strongly induced by serum deprivation and hypoxia in U87 glioma cells in vitro. Our results indicate that anti-angiogenesis in experimental glioma drives expression of critical genes which relate to disease aggressiveness in glioblastoma patients. In particular, CHI3L1 and PI3/elafin may be useful as new prognostic markers and new therapeutic targets.     

A multicenter,observational study of metastatic breast cancer patients who were treated with eribulin mesylate or taxane‐based regimens

1 Aim

This multicenter, observational study aimed to investigate the survival benefit of eribulin as well as that of taxane‐based regimens in Japanese patients with metastatic breast cancer (MBC) in a real‐world setting.

2 Methods

This study enrolled women with MBC who received eribulin or taxane‐based regimens with or without bevacizumab in routine clinical practice from July 2011 to March 2014. Patients were followed until September 2015. The primary endpoint was overall survival (OS). Secondary endpoints included progression‐free survival (PFS), post‐progression survival (PPS) and adverse events. Efficacy findings were adjusted according to demographics.

3 Results

In total, 216 patients receiving eribulin monotherapy (n = 101), taxane monotherapy (n = 73) or taxane plus bevacizumab (n = 42) were followed for a median time of 15.4 months. Median OS, PFS and PPS were 22.3, 8.1 and 14 months in the eribulin monotherapy group; 13.2, 3.6 and 7.6 months in the taxane monotherapy group; and 12.9, 5.7 and 6.3 months, in the taxane plus bevacizumab group, respectively. The incidence of neutropenia was 67.3, 41.1 and 16.7%, and the incidence of grade 4 neutropenia was 1.0, 8.2 and 7.1% in the eribulin monotherapy, taxane monotherapy and taxane plus bevacizumab groups, respectively. One patient (1.0%) discontinued eribulin and 18 patients (15.7%) discontinued taxane‐based regimens because of adverse events.

4 Conclusion

In Japanese MBC patients in a real‐world setting, eribulin showed a survival benefit and tolerability similar to that in previous reports.     

Novel RAF/MEK inhibitor CH5126766/VS-6766 has efficacy in combination with eribulin for the treatment of triple-negative breast cancer

Various molecular-targeting drugs have markedly improved the treatment of patients with breast cancer. As yet, therapies for triple-negative breast cancer are mainly cytotoxic agents. To investigate the novel therapy for triple-negative breast cancer, we herein examined the effects of a new combination therapy comprising a RAF/MEK inhibitor CH5126766, also known as VS-6766, which we originally discovered, and eribulin. The combination of CH5126766 and eribulin potently inhibited cell growth in the triple-negative breast cancer cell lines tested. The underlying mechanism in the efficacy of this combination treatment in vitro and in vivo was due to enhanced apoptosis through the suppression of survivin and Bcl-2 family proteins. We also showed the suppressed expression of programmed cell death ligand 1 (PD-L1) in combination therapy in vivo. We found that combination therapy with eribulin and CH5126766 for triple-negative breast cancer inhibited cell growth by apoptosis and raised a possibility that immune responses through suppression of PD-L1 might partially contribute to inhibition of tumor growth, indicating the potential of this combination as a novel strategy for triple-negative breast cancer.     

Chimeric Mouse model to track the migration of bone marrow derived cells in glioblastoma following anti-angiogenic treatments

Bone marrow derived cells (BMDCs) have been shown to contribute in the tumor development. In vivo animal models to investigate the role of BMDCs in tumor development are poorly explored. We established a novel chimeric mouse model using as low as 5 × 10⁶ GFP+ BM cells in athymic nude mice, which resulted in >70% engraftment within 14 d. In addition, chimera was established in NOD-SCID mice, which displayed >70% with in 28 d. Since anti-angiogenic therapies (AAT) were used as an adjuvant against VEGF-VEGFR pathway to normalize blood vessels in glioblastoma (GBM), which resulted into marked hypoxia and recruited BMDCs to the tumor microenvironment (TME). We exploited chimeric mice in athymic nude background to develop orthotopic U251 tumor and tested receptor tyrosine kinase inhibitors and CXCR4 antagonist against GBM. We were able to track GFP+ BMDCs in the tumor brain using highly sensitive multispectral optical imaging instrument. Increased tumor growth associated with the infiltration of GFP+ BMDCs acquiring suppressive myeloid and endothelial phenotypes was seen in TME following treatments. Immunofluorescence study showed GFP+ cells accumulated at the site of VEGF, SDF1 and PDGF expression, and at the periphery of the tumors following treatments. In conclusion, we developed a preclinical chimeric model of GBM and phenotypes of tumor infiltrated BMDCs were investigated in context of AATs. Chimeric mouse model could be used to study detailed cellular and molecular mechanisms of interaction of BMDCs and TME in cancer.