Inhibition of Notch and HIF enhances the antitumor effect of radiation in Notch expressing lung cancer

Background: The Notch receptor plays an important role in various cell fate decisions during development and in cancer. We have previously reported that Notch3 is upregulated by radiation in non-small cell lung cancer (NSCLC) cell lines and that the Notch pathway inhibitor γ secretase inhibitor GSI (gamma-secretase inhibitor), when combined with radiation therapy, significantly suppressed the growth of lung cancer cells. However, little is known about the mechanism of Notch upregulation induced by radiation. Based on reports of Notch expression being activated through the hypoxia inducible factor 1 (HIF-1) under hypoxic conditions, we hypothesized that HIF-1 would be involved in radiation-induced Notch activation in NSCLC. Methods: Changes in HIF-1 and Notch expression in two Notch expressing NSCLC cells line after radiation treatment were examined using Western blotting. Notch expression was evaluated after the suppression of HIF-1α by small interfering RNA. The cytotoxic effect of YC-1, a HIF inhibitor, GSI and radiation was examined using the MTT assay in vitro and the xenograft model. Result: We found radiation-induced expression of HIF-1α protein at 2-6 h after treatment and upregulated expression of Notch3 protein at 24 h after treatment under hypoxic conditions. Specific suppression of HIF-1α expression downregulated the radiation-induced Notch3 activation, suggesting that the Notch pathway is activated though HIF-1α after radiation. An antitumor effect of YC-1 was evident under hypoxic conditions only when there was simultaneous radiation treatment. GSI and YC-1 had a synergistic antitumor effect in vitro, and the combination of GSI and YC-1 showed the greatest radiosensitivity in vivo. Conclusion: Radiation-induced upregulation of the Notch pathway and HIF-1α protein may be potential therapeutic targets for more effective radiation therapy

Relationship between tumour development and detection of Marek’s disease virus in the feather follicular epithelium of older chickens

To demonstrate the relationship between tumour development and virus replication, eight specific-pathogen-free pullets of line P2 (Group P; 14 weeks old) and five adult chickens (Group A; 96 weeks old) were inoculated with virulent Marek’s disease virus (vMDV). Five chickens of Group P died or were euthanised due to moribund condition following the development of neoplastic lesions between days 53 and 91. On histopathological examination, these lesions were characterised by the proliferation of lymphoid cells of variable size. On analysis by polymerase chain reaction (PCR), the MDV meq gene was detected in Group P from day 21, and it was continuously identified in five chickens until they died or were euthanised. Abnormal signs and histopathological changes were not observed in chickens of Group A. The MDV meq gene was temporarily detected in some chickens of Group A, but it remained almost undetectable throughout the experimental period. In older chickens inoculated with vMDV, the onset of MD lymphoma development tended to be delayed as compared with the young chicks. The relationship between MD lymphoma development and virus replication in older chickens has been suggested. Our data might indicate the underlying existence of an age-related resistance to vMDV challenge

Pathology of spontaneous tumour lesions in pullets and adult chickens in commercial farms — Short communication

Twenty pullets and adult chickens, aged 100 to 403 days, from several commercial chicken farms were examined by gross and histopathology. Grossly, all chickens had white-greyish masses in the visceral organs with or without enlargement of the peripheral nerves. Histopathological examination revealed Marek’s disease (MD) lymphoma, lymphoid leukosis (LL) and myeloid leukosis (ML) in 14/20, 5/20 and 1/20 of the chickens, respectively. Lesions of the sciatic nerves in chickens diagnosed as having MD lymphoma were various. No neoplastic and/or inflammatory cells were noted in the peripheral nerves of chickens diagnosed as having LL and ML. These results indicated that MD lymphoma could also develop in older chickens; thus, microscopic examination is needed to identify MD in older chickens showing lymphocyte-derived tumours

A randomized phase II trial of erlotinib versus S-1 as a third- or fourth-line therapy for patients with wild-type EGFR non-small cell lung cancer (HOT1002)

Purpose: A high proportion of patients with wild-type EGFR non-small cell lung cancer (NSCLC) receive third-line therapy and beyond, with no prospective randomized trials addressing the issue. This study aimed to select the most suitable regimen as a third- or fourth-line therapy for wild-type EGFR NSCLC. Methods: This multicenter, randomized phase II study in Japan included patients with recurrent or advanced NSCLC with wild-type or unknown EGFR, who progressed after two or three previous chemotherapies. The patients were randomly assigned to erlotinib (150 mg/day, days 1-21) or S-1 (80-120 mg/day, days 1-14) every 3 weeks until disease progression or unacceptable toxicity. The primary endpoint was disease control rate (DCR). The secondary endpoints included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), toxicity, and quality of life (QOL). Results: From 2011 to 2016, 37 patients were randomly assigned to receive erlotinib (E arm, n = 19) and S-1 (S arm, n = 18). This study was terminated prematurely because of poor patient accrual. DCR/ORR were 42.1%/15.8% in the E arm and 66.7%/16.7% in the S arm. Median PFS/OS were 1.6 months/8.0 months in the E arm and 3.3 months/12.2 months in the S arm. In both groups, the most commonly reported grade 3-4 toxicities were fatigue, anorexia, and nausea. One grade 5 pneumonitis occurred in the S arm. No significant difference was seen in QOL. Conclusions: S-1 as a third- or fourth-line therapy for wild-type EGFR NSCLC showed numerically better clinical outcomes than erlotinib. Clinical trial registration no. UMIN000005308