Chimori Konaka

LOCALIZATION OF MONO‐L‐ASPARTYL CHLORIN e6 (NPe6) IN MOUSE TISSUES

Abstract It is known that HpD is retained longer by malignant tissue than normal tissue and is therefore a useful material for photodynamic therapy (PDT). Currently, vigorous research is being conducted throughout the world to discover a new material which can have greater cancer cell affinity than hematoporphyrin derivative (HpD) and will be used effectively for PDT. Investigation has been conducted to determine the spectral characteristics and cancer cell affinity of NPe6, a recently developed material.

A Comparison between Argon‐dye and Excimer‐dye Laser for Photodynamic Effect in Transplanted Mouse Tumor

Photodynamic therapy (PDT) utilizing a hematoporphyrin derivative (HpD) as a sensitizer has become a viable option for the local treatment of neoplastic disease. The argon‐dye laser system is commonly used as a light source in this treatment modality. The excimer‐dye laser, on the other hand, delivers high‐energy red light in a pulsatile fashion. In this investigation, we treated BALB/c mice bearing mouse kidney sarcoma cell tumors with PDT using HpD at the dose of 5 mg/kg body weight as a photosensitizer and either a standard argon‐dye laser or the pulsatile excimer‐dye laser as the light source. At equal light energy doses (50 J/cm2), necrotic changes at depths averaging 4 mm from the tumor surface were obtained with the argon‐dye laser (200 mW power output) while tumor necrosis at depths exceeding 15 mm from the tumor surface was obtained using the excimer‐dye laser (6 mJ/pulse, 5 Hz). To determine the best conditions for photoirradiation with the excimer‐dye laser, tumor‐bearing mice were treated with different total light doses (10, 30 and 50 J/cm2), dose rates (1, 3 and 6 mJ/cm2), and frequencies (5,15 and 50 Hz) of light exposure. Our results indicate that the optimal effects obtained with the excimer‐dye laser are related to the total light dose used and the dose rate, but not to the frequency of light exposure.

Increased cytotoxic effects of photodynamic therapy in IL-6 gene transfected cells via enhanced apoptosis

PDT has been reported to induce cancer cell expression of cytokines, such as IL‐6 and TNF‐α, but it has been unclear whether cytokine expression by cancer cells is directly related to the antitumor effect of PDT. We treated Lewis lung carcinoma (LLC) cells with a new photosensitizer, mono‐L‐aspartyl chlorin e6 (NPe6) and light from a diode laser and found that expression of the mRNA of IL‐2, IL‐6, and TNF‐α was increased by NPe6‐mediated‐PDT 6 hr later. To elucidate the mechanism of the direct anti‐tumor effect of cytokine expression, we examined the photosensitivity of cytokine‐gene‐transfected cells, namely LLC‐IL‐2, LLC‐IL‐6, and LLC‐TNF‐α cells, by MTT assay. The IL‐6 gene transfected, LLC‐IL‐6 cells were significantly more sensitive to cytotoxic effects than the parent LLC cells and other cytokine gene‐transfected cells. This finding indicates that IL‐6 expression modulates cellular sensitivity to PDT and that IL‐2 and TNF‐α expressions does not. In addition, the apoptosis of LLC‐IL‐6 cells induced by NPe6‐PDT was greater than in the other cells as determined by DNA fragmentation and staining of apoptotic nuclei. Because IL‐6 has been reported to induce apoptosis by downregulating expression of Bcl‐2, we analyzed the expression of apoptosis‐related Bcl‐2, Bax, and cytochrome C by Western blot analysis. Decreased expression of Bcl‐2 and cytochrome C was observed in both LLC cells and LLC‐IL‐6 cells. Bax protein increased in a time‐dependent manner, and the ratio of Bax to Bcl‐2 rose markedly after PDT in LLC‐IL‐6 cells. These results suggest that the increased sensitivity of LLC‐IL‐6 cells to PDT‐induced cytotoxicity results from the high ratio of Bax to Bcl‐2 in the IL‐6‐dependent apoptotic pathway. In conclusion, IL‐6 expression plays a role in cellular sensitivity to PDT, and combination of IL‐6 and PDT may provide a new strategy for cancer treatment.

Photodynamic therapy for multiple primary bronchogenic carcinoma

In recent years, multiple primary lung cancers have been reported with greater frequency, partly as a result of technologic advances in the detection of lung cancer and therapeutic achievements in its management. Photodynamic therapy (PDT) is a relatively new therapy used with increasing frequency in the treatment of a wide variety of malignancies, including central lung cancers. In PDT, the differential retention of an injected photosensitizer by malignant tissue is exploited by treatment with a low‐power laser beam delivered endoscopically. Since 1980, 145 patients with central lung cancers, including 35 cases of endoscopically evaluated early‐stage lesions were treated with PDT at Tokyo Medical College. Thirteen of these 145 patients had multiple primary bronchogenic carcinomas, five cases of which were synchronous with the rest, metachronous. Three of 13 patients with multiple tumors had early‐stage lesions and were treated with endoscopic PDT alone. In the other ten cases, PDT was used to treat accessible early‐stage foci although operative excision was required for advanced lesions. Mean survival after PDT, alone or in combination with surgery, was 38 months (range, 14 to 87 months), and seven patients remain alive to date. It was concluded that PDT is useful in extending the therapeutic options for, and improving the prognosis of patients with, multiple primary bronchogenic carcinomas.

Influence of E-cadherin dysfunction upon local invasion and metastasis in non-small cell lung cancer.

E-Cadherin (ECD), a transmembrane cell adhesion molecule, is associated with three kinds of cytoplasmic proteins (alpha-catenin, beta-catenin and plakoglobin), and formation of the cadherin-catenins adhesion complex is indispensable for tight cell-to-cell adhesion in adherence junctions. There is a high possibility that dysfunction of ECD reflects increased potential for local invasion and distant metastasis. We investigated the relationship between the expression of cadherin-catenin adhesion complex and the clinicopathological features in 81 cases of non-small cell lung cancer. There were statistically significant relationships between the expression of ECD and lymph node metastasis (P = 0.016) and between the expression of ECD and pathological stage (P = 0.006). Reduction of alpha-catenin expression was associated with local invasion and pathological stage. Dividing the 81 cases into two groups based on ECD function revealed a statistically significant relationship between ECD function and all clinicopathological factors investigated (local tumor invasion P = 0.033, lymph node metastasis P<0.001, pathological stage P<0.001). Evaluation of ECD function using the expression of cadherin-catenin adhesion complex is useful to evaluate tumor malignancy of non-small cell lung cancer.

Early detection of bronchial lesions using system of autofluorescence endoscopy (SAFE) 1000

Recently several endoscopic fluorescence detection systems have been developed. In some of them, laser light was used for the excitation of autofluorescence, and sophisticated techniques were also necessary to amplify the fluorescence signal as well. The result of fluorescence diagnosis using a simple system with a conventional Xenon lamp excitation and an image intensifier is reported. The respective results of sensitivity and positive predictive values of cancer plus dysplasia were 66%, and 62% by standard bronchoscopy and 92% and 88% by the newly developed autofluorescence system. In this paper, developed endoscope for detection of tissue/mucosal autofluorescence without the application of any photosensitizing agents or use of any lasers is evaluated.

Peripheral non-small cell lung cancers 2.0 cm or less in diameter: Proposed criteria for limited pulmonary resection based upon clinicopathological presentation

Clinical features of peripheral non-small cell lung cancer 2.0 cm or less were retrospectively analyzed. Nodal status and prognosis in relation to tumor diameter and histologic type were investigated in 171 consecutive patients with peripheral clinical T1N0M0 non-small cell lung carcinomas 2 cm or less in diameter and who had undergone surgical resection between 1976 and 1997. Of the 171 patients, 136 had adenocarcinoma, 27 had squamous cell carcinoma, four had large cell carcinoma, three had carcinoid and one had adeno-squamous carcinoma. There was no statistically significant difference in the incidence of stage I cases between adenocarcinoma and squamous cell carcinoma. Lymph node involvement was recognized in 30 (17.5%) patients: ten (5.8%) at N1 nodes and 20 (11.7%) at N2 nodes. Lymph node metastasis was significantly more common in tumors 1.5-2.0 cm in diameter (22%) than in those 1.5 cm or less in diameter (14.0%, P = 0.0490). There was no lymph node metastasis in tumors 1.0 cm or less in diameter. The 5-year survival rates cases with or without lymph node involvement were 63.3 and 75.3%, respectively, showing significant difference (P = 0.0338). The result of the present study suggested that systematic mediastinal and hilar lymph node dissection is necessary even for cases with tumor diameter less than 2 cm. However, if the tumor is within 1.0 cm in diameter, mediastinal lymph node dissection might be dispensable; therefore, these cases are good candidates for video-assisted lobectomy.

Malignancy associated changes in bronchial epithelial cells and clinical application as a biomarker

A total of 74 bronchial brushing specimens, 24 from patients with advanced stage cancer, eight from patients with CIS, 31 from patients with atypical metaplasia and 11 from normal subjects were examined for the existence of malignancy associated changes (MAC). Conventional fiberoptic bronchoscopy and fluorescence endoscopy was carried out on every case. Each case was classified according to the highest grade of abnormality diagnosed by bronchial biopsy of the suspect areas. During the endoscopy examination, a bronchial brushing specimen was obtained from a visually normal area very remote from the abnormal area as possible such as the opposite lung or another lobe. The bronchial brushing specimens were fixed, mounted and stained by a DNA specific method and approximately 1500 images of individual nuclei per case were captured by an automated high resolution image cytometry. For each of these images, more than 100 nuclear features such as size, shape and chromatin spatial organization were calculated. Discriminant function analysis revealed nuclear features which differentiated between normal bronchial cell nuclei from the normal subjects and ostensively normal nuclei (MAC cell nuclei) from the lung cancer patients. The best discrimination was achieved when the frequency of individual cells expressing MAC was 50% or greater. With this threshold, 75% of the patients with invasive cancer and CIS were correctly classified. Fifty percent of those with severe or moderate atypia and 35% with mild atypia were also MAC positive. The frequency of cells expressing MAC also increased as the degree of abnormality of the groups increased. MAC may be a useful criterium to determine biological behavior of the intra-epithelial (pre-invasive) neoplasia.

Early detection of bronchial lesions using lung imaging fluorescence endoscope.

The performance of the Lung Imaging Fluorescence Endoscope (LIFE) system was compared with conventional bronchoscopy in 158 patients: 68 patients with invasive cancer, 42 patients with abnormal sputum cytology findings (12 early cancer and 26 dysplasia), 17 cases with resected lung cancer and 31 smokers with symptoms. The respective results of conventional bronchoscopy and LIFE for detection of dysplasia were; sensitivity 52% and 90% (biopsy basis), 62% and 92% (patient basis). Fluorescence bronchoscopy may be an important adjunct to conventional bronchoscopy to improve the localization of subtle lesions of bronchus.

Photodynamic therapy (PDT) in early stage lung cancer

Abstract In order to evaluate the possibility of curative treatment of photodynamic therapy (PDT) in early stage central type lung cancer, 57 lesions in 48 patients were treated with PDT at Tokyo Medical College and 70 lesions at the Hayata Cancer Research Group of the Ministry of Health and Welfare of Japan. Apparent complete remission (CR) was obtained in 71.9% in the former and in 82% in the latter. There was a relationship between CR and the extent and growth type of the tumor. From the therapeutic results in these cases we estimated the indications of PDT in early stage lung cancer as follows. (1) The entire lesion should be visible endoscopically. (2) The tumor should be located at a site to which the laser beam can be delivered easily and sufficiently. (3) The lesion should be superficial and not more than 1.0 cm in diameter. (4) The histologic type should be squamous cell carcinoma. (5) There should be no lymph node involvement.