The role of monoclonal antibody A7 as a drug modifier in cancer therapy

An anticancer antibiotic, neocarzinostatin (NCS), was covalently conjugated to the murine monoclonal antibody A7 (mAb A7), which recognizes the glycoprotein on the cell surface of human colon cancer. The biological and pharmacological properties of the conjugate (A7-NCS) were examined and compared with those of unconjugated NCS. A7-NCS exhibited a strong binding and cytotoxicity to the cell and an antigen-specific tumor accumulation. Significant tumoricidal effects in vivo were observed in the antigen-positive tumor-bearing mice treated with A7-NCS, whereas NCS mixed with mAb A7 and NCS alone were relatively ineffective. In the antigen-negative tumor, the tumoricidal effect of A7-NCS was lower than in the antigen-positive tumor. The NCS concentration in blood and tumor were significantly elevated by conjugation to mAb A7. The NCS localization in tumor was higher in the antigen-positive tumor than in the antigen-negative tumor. Death due to acute toxicity was observed at a dose of 20 units (U) NCS in mice treated with unconjugated NCS, whereas toxicity was seen with a much higher dose of NCS (100 U) if the drug was conjugated to the mAb. These findings show that mAb A7 confers more favorable pharmacological properties on an anticancer drug, making it potentially more useful for cancer chemotherapy.

Surgical treatment of esophageal carcinoma in patients eighty years of age and older

Before 1979, no patient 80 years of age or older had been operated on at our institution for esophageal cancer, while in the middle period (1980-1984), three patients were operated on, and postoperative pulmonary complications and operative death occurred in 66.7 and 33.3%, respectively. However, in the recent period (1985-1990), there was no postoperative morbidity or mortality in the five cases over age 80. On the other hand, there were 12 patients over age 80 who did not undergo operation, of whom all died of cancer. In the eight operated patients over age 80, two cases are still alive 17 and 34 months after operation. According to the above findings, when the patient's general condition is evaluated to be sufficient to tolerate the operation and the cancer is judged to be resectable, esophageal resection is thought to be indicative in all patients over eighty.

Hyperthermo-chemo-radiotherapy as a definitive treatment for patients with early esophageal carcinoma

Ten patients with early stage esophageal carcinoma were treated with hyperthermo-chemo-radiotherapy (HCR) without surgery. The reasons for the inoperability of these patients included medically inoperable unresectable cancers, advanced age, and/or refusal to undergo surgery. The diagnosis of early esophageal carcinoma was determined by esophagograms, endoscopy, and ultrasonography. Squamous cell carcinoma was histopathologically confirmed in each case. Each patient underwent four to nine sessions of hyperthermic treatment combined with external irradiation and chemotherapy using bleomycin; eight of these patients received additional radiation, and two terminated treatment after the HCR therapy. The tumors in all patients showed either a complete response (CR) or a partial response (PR) after HCR therapy; in two patients viable cancer cells remained, but later disappeared after additional radiation. Five patients experienced no local recurrence for 12 to 70 months and are now alive and doing well, three died of other medical conditions without any evidence of esophageal cancer, and two died of recurrent esophageal cancer 20 to 27 months after initial admission. All ten patients tolerated the HCR well without any systemic side effects. However, in two patients, esophageal erosion was recognized endoscopically. HCR therapy therefore deserves serious consideration when treating patients with small malignant lesions of the esophagus who, for various reasons, are unable to undergo surgery.

Local administration of monoclonal antibody-drug conjugate: a new strategy to reduce the local recurrence of colorectal cancer

This report investigates the application of monoclonal antibody A7 and its drug conjugate in locally controlling colorectal cancer. The experimental protocol consisted of local retention, lymphatic delivery, normal organ distribution, systemic toxicity, and tumoricidal effects. When 125I-labeled monoclonal antibody (Mab) A7 was injected into the pelvis and the thigh of Balb/c mice, a high local retention unrelated to antigen-antibody interaction was observed at the injected site for 24 h after injection. An analysis of local retension properties related to antigen-antibody interaction, conducted by intratumorally or peritumorally injecting 125I-Mab A7 into the tumor-bearing athymic nude mice, revealed a significantly higher tumor localization of Mab A7 in comparison to i.v. injection. 125I-Mab A7 accumulated to a great extent in the ipsilateral regional lymph node but not in the contralateral regional lymph node. Normal organ accumulation of Mab A7 was lower in the locally injected group than in the i.v. injected group. Intratumoral injection of Mab A7-neocarzinostatin (A7-NCS) led to the complete remission of established tumor in 5 of 6 antigen-positive xenograft-bearing mice but exhibited a complete remission in only 1 of 6 antigen-negative xenograft-bearing mice. A single local injection of A7-NCS inhibited tumor development in 12 of 16 and 5 of 15 antigen-positive tumor-bearing mice and antigen-negative tumor-bearing mice, respectively, whereas neither a systemic injection of A7-NCS and NCS nor a local injection of NCS and saline had a notable inhibitory effect on tumor development. Systemic toxicity of NCS was markedly reduced when it was locally administered in the antibody-conjugated form. These findings indicate that local injection of immunoconjugate is a promising new field for controlling the local recurrence of colorectal cancer.

Endoscopic diagnosis of early carcinoma of the esophagus using Lugol's solution

Small esophageal lesions, particularly intraepithelial cancers, are extremely difficult to detect. We used Lugol's iodine solution with panendoscopic examination to detect the presence and spread of small squamous cell carcinomas of the esophagus. Serial histologic specimens of the surgically removed esophagus from 32 patients with Lugol's combined endoscopic diagnosis of early esophageal carcinoma were examined to determine the correlation between endoscopic and histologic findings. All of the early staged carcinomas clearly remained unstained by Lugol's solution. We believe that the application of Lugol's solution will greatly aid in instances when a suspicious mucosal lesion is noted, when the margin of the lesion is unclear, or when there is suspicion that a mucosal lesion may have been overlooked.

Synergistic effects of intratumor administration of cis-diamminedichloroplatinum(II) combined with local hyperthermia in melanoma bearing mice

The synergistic effect of local hyperthermia (LHT) with intratumor injection (i.t.) of cis-diamminedichloroplatinum (II) (DDP) was studied using a rodent model with implanted B16 melanoma tumors. The hindfoot of the C57BL/6 mouse bearing the tumor was placed in a water bath at 42.5 +/- 0.2 degrees C (intratumor temperature was at 42.3 +/- 0.1 degrees C) for 30 minutes just after local (i.t.) or systemic (intraperitoneal;i.p.) administration of DDP (1-3 mg/kg once in experiment I and 1-3 mg/kg three times in experiment II). The tumor growth ratio (TGR) at 7 days after treatment in the group given DDP 3 mg/kg (i.t.) with LHT was 1.1 in experiment I and 0.5 in experiment II, and there was a statistically significant difference in both experiments compared to findings in other groups (P < 0.01). The mean survival time was 42.1 days in experiment I and 50.2 days in experiment II, with a significant difference in the latter (P < 0.001). Thus regional injection chemotherapy given concomitantly with local hyperthermia promotes the anticancer effects and improves the prognosis without either severe renal injury or the promotion of hematogenic metastasis.

Crystal structure of papain-E64-c complex. Binding diversity of E64-c to papain S2 and S3 subsites

In order to investigate the binding mode of E64-c (a synthetic cysteine proteinase inhibitor) to papain at the atomic level, the crystal structure of the complex was analysed by X-ray diffraction at 1.9 A (1 A is expressed in SI units as 0.1 nm) resolution. The crystal has a space group P2(1)2(1)2(1) with a = 43.37, b = 102.34 and c = 49.95 A. A total of 21,135 observed reflections were collected from the same crystal, and 14811 unique reflections of up to 1.9 A resolution [Fo > 3 sigma(Fo)] were used for the structure solution and refinement. The papain structure was determined by means of the molecular replacement method, and then the inhibitor was observed on a (2 magnitude of Fo-magnitude of Fc) difference Fourier map. The complex structure was finally refined to R = 19.4% including 207 solvent molecules. Although this complex crystal (Form II) was polymorphous as compared with the previously analysed one (Form I), the binding modes of leucine and isoamylamide moieties of E64-c were significantly different from each other. By the calculation of accessible surface area for each complex atom, these two different binding modes were both shown to be tight enough to prevent the access of solvent molecules to the papain active site. With respect to the E64-c-papain binding mode, molecular-dynamics simulations proposed two kinds of stationary states which were derived from the crystal structures of Forms I and II. One of these, which corresponds to the binding mode simulated from Form I, was essentially the same as that observed in the crystal structure, and the other was somewhat different from the crystal structure of Form II, especially with respect to the binding of the isoamylamide moiety with the papain S subsites. The substrate specificity for the papain active site is discussed on the basis of the present results.

Crystallization and preliminary X-ray study of the cathepsin B complexed with CA074, a selective inhibitor

Cathepsin B from bovine spleen has been purified and crystallized as a complex with a specific inhibitor CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L- isoleucyl-L-proline], using the hanging-drop method. The complex crystals obtained from 50 mM-citrate buffer (pH 3.5) belong to the tetragonal space group P4(1) (or P4(3)) with a = 73.06 A and c = 141.59 A, and diffract beyond 2.2 A resolution. There are two complex molecules per asymmetric unit giving a packing density of 3.37 A3/Da and indicating a high solvent content of 63.5%.

Monoclonal antibody-drug conjugate therapy for the patients with colorectal cancer

Monoclonal antibody drug conjugate A7 was prepared from a mouse splenocyte immunized against human colon cancer. A7 reacted with 80 percent of colorectal cancer and pancreatic cancer. A7 was bound covalently to neocarzinostatin (NCS) to form A7-NCS. A7-NCS had strong cytotoxic activity in vivo and in vitro study. A total of 77 patients with colorectal cancer, including the patients with liver, lung and peritoneal metastasis, were treated with A7-NCS. There were some tumor reduction of liver metastasis on CT scan and pain relief. Follow up study of colorectal cancer patients treated with monoclonal antibody drug conjugate A7-NCS was carried out, with comparing to those treated conventional chemotherapy. Survival rate of the patients with postoperative liver metastasis treated with A7-NCS was slightly higher than that of the patients treated with conventional intraarterial infusion chemotherapy. There was no difference between the group treated with A7-NCS and that treated with conventional chemotherapy in the overall postoperative survival. Patients given a higher dose of the conjugate had a higher survival rate. There were no serious adverse effects in the patients given A7-NCS. Human anti-mouse antibody (HAMA) was detected in all A7-NCS treated patients.

Production of a monoclonal antibody that defines the alpha-subunit of the feline IL-2 receptor

A mAb, termed 9F23, to feline Con A-stimulated PBMC was prepared to characterize feline IL-2R. 9F23 was identified by FACS studies, which showed that the antigen was expressed at a high density on Con A-induced feline T cell blasts while 9F23 binding was not detected on nonactivated PBMC or the Crandell feline kidney cell line CRFK. Chemical crosslinking of 125I-IL-2 to membrane IL-2Rs on Con A-stimulated feline PBMC under the low-affinity condition resulted in detection of a major 65-kDa band. 9F23 specifically immunoprecipitated the IL-2.IL-2R alpha complex in a cell extract; in contrast, neither anti-human IL-2R alpha H48 nor anti-mouse IL-2R alpha 7D4 reacted with the complex. Moreover, immunoprecipitation with 9F23 of the extract from surface-iodinated Con A-stimulated PBMC showed a major 50-55 kDa band. Furthermore, 9F23 had no effect on either IL-2-driven proliferation of the Con A-stimulated PBMC or IL-2 binding. Finally, the expression of feline IL-2R alpha on Con A-stimulated PBMC was up-regulated by addition of exogenous IL-2. Thus, 9F23 defines an epitope different from the IL-2 binding site on the alpha-subunit of feline IL-2R.

Pathology of chemically induced chronic active hepatitis in mice

Female Swiss mice were treated for 24 weeks, with 3-hydroxy-4-pyrone (Py) added to their powdered diet at 0.5% (wt/wt), and the effects of this agent on the liver were examined. Serum transaminases (especially GPT) rose continuously, while the GOT/GPT ratio remained at approximately 1.0 throughout the study period. The characteristic changes found from 8 weeks onward were piecemeal necrosis and bridging necrosis of the hepatocytes with dense lymphocytic infiltration. Proliferation of collagen fibers in the portal tracts and formation of narrow fibrous septa dividing the lobules into pseudolobules were also noted from 12 weeks onward. A large number of the infiltrating lymphocytes were identified as T cells by immunohistochemical and electron microscopic studies. These lymphocytes often surrounded or were closely attached to degenerating hepatocytes. Focal apoptosis and necrosis accompanied by a granulomatous reaction of the centrilobular hepatocytes were noted as early changes in the liver. Our findings indicate that the hepatic changes produced in mice by long-term Py administration have characteristics in common with those of human chronic active hepatitis. Immunological cytotoxic mechanisms, especially T cell-mediated ones, appear to play an essential role in the development of hepatic lesions in this murine model of chronic active hepatitis.

Organ distribution and characterization of porcine peptides (VIP, CGRP and PHI) that increase cAMP in rat platelets

Using an assay for rat platelet cAMP, we investigated the organ distribution of peptides that increase cAMP in rat platelets in porcine tissues. Marked activity was observed in the duodenum, pancreas and brain. By analysis with reverse phase high performance liquid chromatography (HPLC), three major peaks of activity were observed in porcine tissues. The first peak was vasoactive intestinal polypeptide (VIP), and the second peak was calcitonin gene-related peptide (CGRP). The third peak of activity was isolated from porcine duodenum. By analysis with a gas phase sequencer and with an amino acid analyzer, this peptide was identified as peptide histidine isoleucine (PHI). In a glucagon-secretin family of neuropeptides, pituitary adenylate cyclase activating polypeptide (PACAP) significantly increased platelet cAMP levels in a dose-dependent manner; however, glucagon did not. These results suggest that not only VIP and CGRP but also PHI and PACAP act upon platelets, as well as vascular tissues.

[Mode of origin of esophageal squamous cell carcinoma--serial histopathologic and immunohistochemical studies]

I. Serial histopathologic study of esophageal squamous cell carcinoma. A review of 335 cases of squamous cell carcinoma disclosed 55 cases (16.4%) with glandular components in addition to the ordinary component of squamous cell carcinoma, suggesting that this type of esophageal tumor had originated not only from the covering squamous epithelium but from esophageal gland or ductal epithelium. Intra-epithelial carcinoma concomitant with squamous cell carcinoma was seen in 95 cases (28.4%). The incidences of coexistence in such lesion were higher in the groups of early stage esophageal cancer. These observations support the concept of field carcinogenesis of esophageal cancer. II. Histopathologic study of squamous epithelial dysplasia. Among 91 cases without preoperative treatment, there were 40 dysplastic lesions in 23 cases (25.3%). The continuity of dysplasia to the carcinoma was 48.3% and it was often encountered in severe dysplasia rather than in moderate or mild dysplasia, suggesting some relationship between the severity of dysplasia and carcinoma. III. Immunohistochemical study of EGF and c-myc. Among 27 cases, EGF was positive in 10 (37.0%). c-myc was positive in 18 (66.7%) not only cancer but normal epithelium suggesting that some change of products of oncogene occurred also in the normal epithelium of the patients of esophageal cancer.

Roles of inositol trisphosphate and protein kinase C in the spontaneous outward current modulated by calcium release in rabbit portal vein

We examined the effects of heparin, guanosine nucleotides, protein kinase C (PKC) modulators, such as phorbol 12,13-dibutyrate (PDBu) and H-7 on Ca(2+)-dependent K+ currents in smooth muscle cells of the rabbit portal vein using the whole-cell patch-clamp technique, to explore the effects of PKC on the oscillatory outward current (Ioo). Neomycin (30 microM), an inhibitor of phospholipase C, and intracellular applications of heparin (10 micrograms/ml) and guanosine 5'-O-(2-thiodiphosphate) (GDP[beta S]; 1 mM) partly but consistently inhibited the generation of Ioo, whereas a higher concentration of heparin (100 micrograms/ml) transiently enhanced then suppressed the generation of Ioo. Inhibition of Ioo generation by heparin was more powerful at the holding potential of +20 mV than at -20 mV. Inositol 1,4,5-trisphosphate (InsP3; 30 microM) continuously generated Ioo at holding potentials more positive than -60 mV. Noradrenaline (10 microM) and caffeine (3-20 mM) transiently augmented, then reduced the generation of Ioo. Heparin (10 micrograms/ml) completely inhibited responses induced by InsP3 and noradrenaline, but not those induced by caffeine. Intracellular application of guanosine 5'-triphosphate (GTP; 200 microM) or low concentrations of guanosine 5'-O-(3-thiotriphosphate) (GTP[gamma S]; < or = 3 microM) continuously augmented the generation of Ioo. High concentrations of GTP[gamma S] (> or = 10 microM) transiently augmented, then inhibited Ioo. Neither GTP[gamma S] nor noradrenaline induced the transient augmentation or the subsequent inhibition of Ioo when applied in the presence of GDP[beta S] (1 mM), neomycin (30 microM) or heparin (10 micrograms/ml). PDBu (0.1 microM) reduced the generation of Ioo but failed to produce an outward current following application of caffeine (3-5 mM). This action of PDBu was inhibited by pretreatment with H-7 (20 microM). In the presence of H-7, GTP[gamma S] continuously enhanced the generation of Ioo. The suppression of the generation of Ioo during application of noradrenaline (10 microM) was reduced by pretreatment with H-7. Thus both InsP3 and protein kinase C contribute to the generation of Ioo in smooth muscle cells of the rabbit portal vein and heparin is not a specific InsP3 antagonist on the InsP3-induced Ca(2+)-release channel (PIRC). InsP3 opens PIRC and protein kinase C may deplete the stored Ca2+ by either inhibiting the reuptake of Ca2+ or by enhancement of the releasing actions of InsP3.