Atsuro Saijo

Dll4-Fc, an Inhibitor of Dll4-Notch Signaling, Suppresses Liver Metastasis of Small Cell Lung Cancer Cells through the Downregulation of the NF-κB Activity

Notch signaling regulates cell-fate decisions during development and postnatal life. Little is known, however, about the role of Delta-like-4 (Dll4)-Notch signaling between cancer cells, or how this signaling affects cancer metastasis. We, therefore, assessed the role of Dll4-Notch signaling in cancer metastasis. We generated a soluble Dll4 fused to the IgG1 constant region (Dll4-Fc) that acts as a blocker of Dll4-Notch signaling and introduced it into human small cell lung cancer (SCLC) cell lines expressing either high levels (SBC-3 and H1048) or low levels (SBC-5) of Dll4. The effects of Dll4-Fc on metastasis of SCLC were evaluated using a mouse model. Although Dll4-Fc had no effect on the liver metastasis of SBC-5, the number of liver metastasis inoculated with SBC-3 and H1048 cells expressing Dll4-Fc was significantly lower than that injected with control cells. To study the molecular mechanisms of the effects of Dll4-Fc on liver metastasis, a PCR array analysis was conducted. Because the expression of NF-κB target genes was affected by Dll4-Fc, we conducted an electrophoretic mobility shift assay and observed that NF-κB activities, both with and without stimulation by TNF-α, were downregulated in Dll4-Fc–overexpressing SBC-3 and H1048 cells compared with control cells. Moreover, Dll4-Fc attenuates, at least in part, the classical and alternative NF-κB activation pathway by reducing Notch1 signaling. These results suggest that Dll4-Notch signaling in cancer cells plays a critical role in liver metastasis of SCLC by regulating NF-κB signaling. Mol Cancer Ther; 11(12); 2578–87. ©2012 AACR.

Surfactant Protein A Suppresses Lung Cancer Progression by Regulating the Polarization of Tumor-Associated Macrophages

Surfactant protein A (SP-A) is a large multimeric protein found in the lungs. In addition to its immunoregulatory function in infectious respiratory diseases, SP-A is also used as a marker of lung adenocarcinoma. Despite the finding that SP-A expression levels in cancer cells has a relationship with patient prognosis, the function of SP-A in lung cancer progression is unknown. We investigated the role of SP-A in lung cancer progression by introducing the SP-A gene into human lung adenocarcinoma cell lines. SP-A gene transduction suppressed the progression of tumor in subcutaneous xenograft or lung metastasis mouse models. Immunohistochemical analysis showed that the number of M1 antitumor tumor-associated macrophages (TAMs) was increased and the number of M2 tumor-promoting TAMs was not changed in the tumor tissue produced by SP-A-expressing cells. In addition, natural killer (NK) cells were also increased and activated in the SP-A-expressing tumor. Moreover, SP-A did not inhibit tumor progression in mice depleted of NK cells. Taking into account that SP-A did not directly activate NK cells, these results suggest that SP-A inhibited lung cancer progression by recruiting and activating NK cells via controlling the polarization of TAMs.

Thymidine Phosphorylase Regulates the Expression of CXCL10 in Rheumatoid Arthritis Fibroblast‐like Synoviocytes

Thymidine phosphorylase (TP) in rheumatoid arthritis (RA) fibroblast‐like synoviocytes (FLS) is induced by tumor necrosis factor α (TNFα) and other cytokines that have been reported to be major inflammation mediators in RA. We previously demonstrated that TP plays an important role in angiogenesis and tumor growth, invasion, and metastasis. The aim of this study was to investigate whether the role of TP in the pathogenesis of RA is similar to its role in tumors.

Fibrocyte-like cells mediate acquired resistance to anti-angiogenic therapy with bevacizumab

Bevacizumab exerts anti-angiogenic effects in cancer patients by inhibiting vascular endothelial growth factor (VEGF). However, its use is still limited due to the development of resistance to the treatment. Such resistance can be regulated by various factors, although the underlying mechanisms remain incompletely understood. Here we show that bone marrow-derived fibrocyte-like cells, defined as alpha-1 type I collagen-positive and CXCR4-positive cells, contribute to the acquired resistance to bevacizumab. In mouse models of malignant pleural mesothelioma and lung cancer, fibrocyte-like cells mediate the resistance to bevacizumab as the main producer of fibroblast growth factor 2. In clinical specimens of lung cancer, the number of fibrocyte-like cells is significantly increased in bevacizumab-treated tumours, and correlates with the number of treatment cycles, as well as CD31-positive vessels. Our results identify fibrocyte-like cells as a promising cell biomarker and a potential therapeutic target to overcome resistance to anti-VEGF therapy.

Analysis of acute exacerbation of interstitial lung disease associated with chemotherapy in patients with lung cancer: A feasibility of S-1

BACKGROUND Interstitial lung disease (ILD) is commonly concomitant with lung cancer, and its acute exacerbation (AE) is the most serious complication in patients receiving treatment for lung cancer. METHODS To investigate the incidence and characteristic features of AE of ILD, we conducted a retrospective study of 665 consecutive patients with lung cancer who were treated at our institute between 2008 and 2014. RESULTS Among the 665 patients, 74 (11.1%) had preexisting ILD, and 64 of them received chemotherapy. Four of the 64 patients (6.3%) had experienced AE of ILD, and two (3.1%) died of respiratory failure during first-line chemotherapy. The use of a combination of carboplatin with tegafur-gimeracil-oteracil potassium (S-1) or paclitaxel as a first-line chemotherapy for non-small cell lung cancer led to a lower frequency of AE, at 8.3% (1/12) and 9.1% (1/11), respectively. The incidence of AE rose to 12.8% (5/39) during second-line treatment, and 14 (total: 15 times) of the 64 patients (21.9%) experienced AE from the time of diagnosis to the end of treatment. The incidence of AE was 17.7% (6/34), 15.8% (3/19), 5.0% (2/40), and 4.2% (1/24) in the paclitaxel-, vinorelbine-, etoposide-, and S-1-containing regimens, respectively. No difference in clinical features and laboratory data was detected between the AE and non-AE groups. CONCLUSIONS Although this was a small retrospective study, its findings showed that S-1 and etoposide may be relatively safe options for the treatment of patients with lung cancer and concomitant ILD.

Bone marrow-derived fibrocytes promote stem cell-like properties of lung cancer cells

Cancer stem cells (CSCs) represent a minor population that have clonal tumor initiation and self-renewal capacity and are responsible for tumor initiation, metastasis, and therapeutic resistance. CSCs reside in niches, which are composed of diverse types of stromal cells and extracellular matrix components. These stromal cells regulate CSC-like properties by providing secreted factors or by physical contact. Fibrocytes are differentiated from bone marrow-derived CD14+ monocytes and have features of both macrophages and fibroblasts. Accumulating evidence has suggested that stromal fibrocytes might promote cancer progression. However, the role of fibrocytes in the CSC niches has not been revealed. We herein report that human fibrocytes enhanced the CSC-like properties of lung cancer cells through secreted factors, including osteopontin, CC-chemokine ligand 18, and plasminogen activator inhibitor-1. The PIK3K/AKT pathway was critical for fibrocytes to mediate the CSC-like functions of lung cancer cells. In human lung cancer specimens, the number of tumor-infiltrated fibrocytes was correlated with high expression of CSC-associated protein in cancer cells. These results suggest that fibrocytes may be a novel cell population that regulates the CSC-like properties of lung cancer cells in the CSC niches.

A Case of IgA Nephropathy after Nivolumab Therapy for Postoperative Recurrence of Lung Squamous Cell Carcinoma

Immune checkpoint inhibitors (ICIs) are becoming a common and important cancer therapy. ICIs are associated with a unique category of side effects, termed immune-related adverse events (irAEs). We herein report the case of a 72-year-old man with postoperative recurrence of lung squamous cell carcinoma who was treated with nivolumab and who developed proteinuria and a worsening kidney function. A kidney biopsy revealed IgA nephropathy. After drug withdrawal, the proteinuria improved and the deterioration of the patients renal function was halted. Although renal irAEs are considered to be rare and glomerulonephritis is not typical presentation, physicians need to pay more attention to renal irAEs and glomerular injury.

An analysis of the clinical features of lung cancer in patients with connective tissue diseases

BACKGROUND Patients with connective tissue diseases (CTDs) are at increased risk for lung cancer (LC); interstitial lung disease (ILD) is a common form of organ dysfunction in cases of CTD. However, the influence of ILD on the treatment and prognosis in LC patients with CTD is unclear. METHODS Between January 2010 and December 2014, 27 patients among all patients with CTD at our institution were diagnosed with primary LC. We retrospectively analyzed the clinical features, treatment modalities, and outcomes of these patients, and evaluated the potential prognostic factors. Forty-four LC patients without CTD were also analyzed as a control cohort. RESULTS LC patients with CTD had a significantly higher incidence of ILD as a complication compared with those without CTD (52% and 14%, respectively). CTD-associated ILD (CTD-ILD) at diagnosis was associated with significantly worse survival in LC patients with CTD. Multivariate analysis demonstrated that the complication of CTD-ILD was an independent poor prognostic factor in LC patients with CTD. The incidence of acute exacerbation (AE) of CTD-ILD was 21% among LC patients with CTD, and all of these patients died despite intensive treatment including high-dose corticosteroids. The restrictions in curative therapy for LC due to the presence of ILD and AE of CTD-ILD were thought to be the major reasons for the poor outcome. CONCLUSIONS LC patients with CTD had a high prevalence of ILD, and the presence of CTD-ILD was significantly associated with poor prognosis.

Thymidine catabolism promotes NADPH oxidase-derived reactive oxygen species (ROS) signalling in KB and yumoto cells

Thymidine phosphorylase (TP) is a rate-limiting enzyme in the thymidine catabolic pathway. TP is identical to platelet-derived endothelial cell growth factor and contributes to tumour angiogenesis. TP induces the generation of reactive oxygen species (ROS) and enhances the expression of oxidative stress-responsive genes, such as interleukin (IL)-8. However, the mechanism underlying ROS induction by TP remains unclear. In the present study, we demonstrated that TP promotes NADPH oxidase-derived ROS signalling in cancer cells. NADPH oxidase inhibition using apocynin or small interfering RNAs (siRNAs) abrogated the induction of IL-8 and ROS in TP-expressing cancer cells. Meanwhile, thymidine catabolism induced by TP increased the levels of NADPH and intermediates of the pentose phosphate pathway (PPP). Both siRNA knockdown of glucose 6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme in PPP, and a G6PD inhibitor, dihydroepiandrosterone, reduced TP-induced ROS production. siRNA downregulation of 2-deoxy-D-ribose 5-phosphate (DR5P) aldolase, which is needed for DR5P to enter glycolysis, also suppressed the induction of NADPH and IL-8 in TP-expressing cells. These results suggested that TP-mediated thymidine catabolism increases the intracellular NADPH level via the PPP, which enhances the production of ROS by NADPH oxidase and activates its downstream signalling.

Analysis of the Prognostic Factors of Extensive Disease Small-Cell Lung Cancer Patients in Tokushima University Hospital.

BACKGROUND Small-cell lung cancer (SCLC) presents aggressive clinical behavior, and its prognosis is still poor. Previously, performance status (PS), or the existence of brain, bone, or liver metastasis were reported to be unfavorable prognostic factors. Given the recent progress of treatment modalities such as radiotherapy techniques and bone modifying agents, the prognostic factors might be different from previous findings. Therefore, we analyzed the prognostic factors of extensive disease SCLC (ED-SCLC) in recent years. METHODS ED-SCLC patients treated in Tokushima University Hospital between 2010 and 2016 were analyzed. Log-rank test and the Cox proportional hazards regression model was used in univariate and multivariate analysis, respectively. RESULTS Totally, 79 patients were analyzed. In the univariate analysis, age, PS, interstitial pneumonia (IP), liver metastasis, pleural dissemination, neutrophil counts, hypoalbuminemia, hypercalcemia and several liver and biliary enzymes were identified as poor prognostic factors. In the multivariate analysis, age, PS, IP, and liver and biliary enzymes were identified. Moreover, the PS in patients with liver metastasis was significantly worsened. CONCLUSIONS In this study, we newly demonstrated that IP was a significant poor prognostic factor of ED-SCLC. Although liver metastasis was not extracted in multivariate analysis, it may have an impact on the prognosis of ED-SCLC. J. Med. Invest. 63: 286-293, August, 2016.