Susumu Kodaira

Growth of human tumor xenografts in nude mice and mice with severe combined immunodeficiency (SCID)

Twenty-three fresh tumor specimens obtained at surgery and 5 serially transferable human tumor xenografts were implanted subcutaneously into nude mice and mice with severe combined immunodeficiency (SCID) to compare the take rates of the fresh surgical specimens and the growth rates of the transferable strains. The overall take rates were 65% for the SCID mice and 60% for the nude mice, without any significant difference, although colon carcinoma seemed to have higher acceptance in the SCID mice with a take rate of 6/8. All the serially transferable strains were successfully accepted in the SCID mice, their growth rates being essentially identical to those in the nude mice. These results indicate that the SCID mouse can be used as a human tumor xenograft-mouse system as well as the nude mouse.

Randomized phase III trial of treatment duration for oral uracil and tegafur plus leucovorin as adjuvant chemotherapy for patients with stage IIB/III colon cancer: final results of JFMC33-0502

While adjuvant chemotherapy is preferable for colon cancer, treatment duration is controversial. This phase III trial is investigated optimal duration of adjuvant chemotherapy for Stage IIB/III colon cancer. Eighteen-month treatment with UFT/LV did not improve DFS compared with 6-month UFT/LV treatment. This study suggests that 6 months treatment duration is enough for Stage IIB/III colon cancer.

Randomized trial of the efficacy of adjuvant chemotherapy for colon cancer with combination therapy incorporating the oral pyrimidine 1-hexylcarbamoyl-5-fluorouracil

Background and aimsThe purpose of the present trial was to clarify the efficacy of postoperative adjuvant chemotherapy including an oral fluoropyrimidine anticancer drug, the 1-hexylcarbamoyl-5-fluorouracil (HCFU), for the treatment of colon cancer.MethodPatients with clinical stage Dukes’ B and C colon cancer, who had been treated surgically, were assigned to a chemotherapy group treated with mitomycin C, 5-fluorouracil (5-FU), and HCFU and to a control group that received no postoperative adjuvant chemotherapy.ResultsOf the 1,001 patients registered for the study, 17 (1.7%) were ineligible. The incidence of toxicity was significantly higher in the chemotherapy group than in the control group. However, there were few severe side effects and no deaths related to the treatment. Overall survival showed no significant difference between the groups. The disease-free survival or the recurrence-free intervals was significantly higher in the chemotherapy group than in the control group. The incidence of hepatic recurrence was significantly (P=0.003) lower in the chemotherapy group than in the control group.ConclusionThe results of this study demonstrated the efficacy of adjuvant chemotherapy for colon cancer, i.e., combined chemotherapy that included the 5-FU oral anticancer drug HCFU.

Sandwich Radioimmunometric Assay with Murine Monoclonal Antibody, NCC-ST-439, for Serological Diagnosis of Human Cancers

Sandwich radioimmunometric assay (RIA) for a new tumor‐associated carbohydrate antigen defined by a monoclonal antibody (MoAb), NCC‐ST‐439, was developed and the antigen levels were determined in sera of normal donors, and patients with various malignant and non‐malignant disorders. In normal donors, 97.0% (226/233) of sera were antigen‐negative (less than 12 units/ml) except for 7 serum samples from young females. In patients with malignant disorders, 34.2% (82/240) were antigen‐positive, in particular 64.0% (16/25) of patients with pancreatic carcinoma, 66.7% (16/24) of patients with recurrent colorectal carcinoma and 54,5% (6/11) of patients with recurrent breast carcinoma. In patients with non‐malignant disorders, 6.0% (7/116) were antigen‐positive. The positive rate in benign hepatobiliary disorders, including gallstones, hepatitis and liver cirrhosis, was especially low at 4.3% (1/23). We concluded that determination of serum NCC‐ST‐439 antigen would be useful in serodiagnosis of carcinoma patients.

High Human IgG Levels in Severe Combined Immunodeficient Mouse Reconstituted with Human Splenic Tissues from Patients with Gastric Cancer

We implanted normal peripheral blood lymphocytes (PBL) from healthy donors and splenic tissues from patients with gastric cancers into the severe combined immunodeficient (SCID) mouse, demonstrating that SCID mouse with splenic tissue can produce a high level of human immuno‐globulin G (IgG). The normal PBLs at 107 and 108/mouse were implanted intraperitoneally, and three splenic tissues with a size of 3×3×3 mm from gastric cancer patients were inoculated subcutaneously into the bilateral backs of the mice. At 2, 4, 6 and 8 weeks after inoculation, mice were killed, and the human IgG was assessed by an ELISA method. SCID mice with splenic tissue revealed high human IgG levels from 2 weeks after inoculation and approximately 2 mg of IgG per ml was observed at 8 weeks post‐implantation, while the IgG levels in mice treated with PBLs were limited. Since the half life of the extrinsic human IgG was 10.2 days, the high level of human IgG in the SCID mice was supposed to be produced by human plasma cells in the splenic tissue from gastric cancer patients. This model was thought to be adequate for evaluating human immunological functions in vivo.

Pharmacokinetic analysis of antibody localization in human colon cancer: Comparison with immunoscintigraphy

The biodistribution and imaging characteristics of the111In-labeled anti CEA monoclonal antibody ZCE-025 were studied in five patients with suspicion of colorectal carcinoma. Evaluation included antibody pharmacokinetics and assessment of antibody distribution in surgical specimen, making a comparison with whole-body imaging with a gamma camera. ZCE-025 localization in tumors was demonstrated by gamma-camera imaging in 4 of the 5 patients, corresponding to surgical findings. Persistent accumulation of111In in the lymph nodes was observed in one patient, whereas surgical exploration of these lymph nodes showed no gross or microscopic evidence of metastases of colon carcinoma. Analysis of individual plasma by size exclusion HPLC showed two radioactivity peaks, labeled antibody and free DTPA. No transchelation of111In to circulating transferrin was observed. The blood clearance was fitted to a two-compartment equation and its half-lives were found to be 10.8±8.7 h and 69.5±21.8 h for t1/2α and t1/2β, respectively. Total urinary excretion averaged 0.3% of the injected dose/h with a small patient to patient variation. At 24 hrs postadministration the predominant radiolabeled species in urine was free DTPA. Thereafter, radioactivity in urine was partly present as a low molecular weight catabolic product. No apparent correlation between CEA content and uptake of111In-ZCE-025 in tumors resected by surgery could be found. How111In-labeled antibody is accumulated into tumors as well as into some non-tumor tissues needs further study.

Nude mouse resists hepatic metastasis of the allogeneic tumor, colon-26

The ability of the host-immune defense mechanism of nude mice and their immunocompetent littermates to prevent liver metastases from the murine colon carcinoma, colon-26, was assessed. Give thousand tumor cells suspended in 0.05 ml of Hanks balanced salt solution were inoculated into the spleens of BALB/c nu/+and BALB/c nu/nu mice. On the 21st day after inoculation, all the mice were sacrificed, and the liver metastases counted and the livers weighed. All the BALB/c nu/+mice were found to have developed hepatic metastases with a mean of 10 nodules, whereas no hepatic metastases were observed in any of the 10 BALB/c nude mice. On the other hand, 4 of 6 nude mice developed hepatic metastases after treatment with anti-asialo GM1 antibody. These results indicate that the BALB/c nude mouse has an excellent host-immune defense mechanism for preventing liver metastasis, with NK cells in the liver and/or blood circulation perhaps playing an important role.

The modulation by L-leucovorin of 5-fluorouracil antitumor activity on human colon carcinoma cells in vitro and in vivo

We investigated the modulating effect of L-leucovorin (LV) on the antitumor effect of 5-fluorouracil (5-FU) against human colon carcinoma cells (C-1) in vitro and human colon carcinoma xenografts (Co-4) in nude mice. The modulating effect of LV on 5-FU reached an optimal concentration of 40–80 μg/ml in vitro which was detected by a colorimetric MTT assay. An optimal dose of 200 mg/kg was also observed in the nude mouse system. The modulating effect of LV increased according to the increment of thymidylate synthetase inhibition in vivo. Since the pharmacokinetic pattern of LV in the nude mice administered LV at 200 mg/kg was similar to that in patients treated with LV at a dose of 100 mg/m2, this clinical method of administration was thought to be adequate for modulating the antitumor activity of 5-FU against clinical colon carcinomas.

Two cases of rectal carcinoma associating aorto-iliac occlusive disease

Two cases of rectal carcinoma associating aorto-iliac occlusive disease are presented. These two cases had complete obstruction of the affected vessels, but many collateral pathways from the aorta to the legs had developed, mainly through the superior rectal artery or parietal vessels. Changes in blood flow to the legs, following the radical operation for rectal carcinoma, were examined by both preoperative angiography and perioperative Doppler flow meter. Vascular reconstruction was carried out in one case prior to resection of the rectum, in order to prevent the ischemic legs from becoming worse, or necrotic. The indications for supportive vascular surgery in the case of rectal carcinoma with aorto-iliac occlusive disease are discussed herein.

The expression of stage-specific embryonic antigen 1 in the noncancerous colorectal epithelia of familial polyposis coli

The epithelial expression of carbohydrate antigen, stage-specific embryonic antigen 1 (SSEA-1) was examined immunohistochemically in noncancerous specimens from patients with familial polyposis coli, and compared with the colorectal epithelia from patients with sporadic colorectal cancer. In mucosa remote from carcinoma of sporadic cases, SSEA-1 was expressed only faintly in the lower crypts. In mucosa adjacent to carcinoma of sporadic cases, SSEA-1 was expressed not only in the lower crypts but also in the upper crypts. These results corresponded to those observed in the authors previous study. In the flat mucosa of familial polyposis coli cases, SSEA-1 was detected not only in the lower crypts, but also in both upper crypts and the surface epithelium in contrast with the flat mucosa of sporadic cases. The staining pattern in the upper crypts of the flat mucosa of familial polyposis coli cases was very similar to that of the mucosa adjacent to carcinoma of sporadic cases, but was stronger and more diffuse in the surface epithelium. In microscopic adenomas, SSEA-1 was expressed diffusely. These results demonstrate that the flat mucosa of patients with familial polyposis coli shows preneoplastic changes similar to those in the mucosa adjacent to carcinoma of sporadic cases, and that SSEA-1 is related to adenoma formation in the early stage of carcinogenesis in the colorectum. In addition, the results suggest that immunohistochemical studies of flat mucosa may be useful for the early detection of high-risk individuals in a familial polyposis coli family.