Potentiation by squalene of antitumor effect of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-nitros ourea in a murine tumor system

The effect of squalene (SQ) on the antitumor activity of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitros our ea (ACNU) was studied in a murine tumor system. SQ at 4.2 g/kg exhibited a significant potentiating effect on the activity of 10 mg/kg of ACNU against lymphocytic leukemia P388 and resulted in some long-term survivors without toxicity to the host. Simultaneous administration of SQ and ACNU was most effective.

Potentiation by vitamin A of the action of anticancer agents against murine tumors

Combinations of retinol palmitate (RP) and six different anticancer agents were examined to determine their effects on the life-span of mice bearing ascites sarcoma 180 or P388 leukemia. With ascites sarcoma 180, administration of a fixed dose of RP (3.3 mg/kg) considerably enhanced the antitumor effects of 5-fluorouracil (5-FU) (5 mg/kg, or 20 mg/kg), methotrexate (MTX) (0.5 mg/kg, or 1 mg/kg) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) (12.5 mg/kg), when given by intraperitoneal injection. However RP failed to potentiate the antitumor effects of adriamycin (ADM) and 6-mercaptopurine (6-MP) against sarcoma 180. With P388 leukemia, RP (167 mg/kg, or 333 mg/kg) enhanced the antitumor effects of 6-MP (25 mg/kg, or 50 mg/kg), MTX (1 mg/kg, or 2 mg/kg), ADM (0.2 mg/kg), ACNU (5 mg/kg) and cis-dichlorodiammine-platinum (CDDP) (1 mg/kg) to a considerable extent, but it did not potentiate the antitumor effect of 5-FU. The combination of RP with ACNU or CDDP was particularly effective against P388 leukemia.

[Colony assay for clinical application]

For use in routine clinical studies, modifications to Salmon and Hamburger's human tumor stem cell assay were made. A multiplate with 24 wells made the handling of a large number of samples feasible. The addition of anticancer drugs to the bottom layer of agar facilitated avoidance of exposure to drugs before cell plating and evaluation of the effect of long-acting drugs such as 5-fluorouracil. Storage of test plates including anticancer drugs in a freezer produced no loss of colony-forming activity. Specimens from 32 patients with advanced malignancies of the GI tract were tested for sensitivity to anticancer drugs. Forty-seven percent formed enough colonies for the performance of drug testing. Two patients showed sensitivity to drugs from both in vitro and in vivo results; the ascites in one disappeared while the other showed more than 50 percent regression of hepatic metastatic foci after treatment with suitable drugs. Nine patients showed resistance to drugs from both in vitro and in vivo results. Eight showed resistance to all tested drugs.

Reduced drug accumulation in multiply drug-resistant human KB carcinoma cell lines

Human KB cells with increasing resistance to colchicine and other chemotherapeutic agents have been isolated in four sequential steps. This report describes the characterization of drug uptake in the parent and four mutant cell lines. Drug uptake in these cell lines occurred via a nonsaturable process. In general, drug accumulation decreased with increasing drug resistance; this relationship was seen best with colchicine, vincristine, vinblastine, and daunomycin and, to a lesser extent, with actinomycin D. The accumulation of dexamethasone, an agent to which all lines were equally sensitive, was similar for the parent and the four mutants. Drug efflux occurred rapidly, and differences among the various cell lines could be detected within the first minute. In the more resistant lines, a greater percentage of the drug was released more rapidly, although the absolute amount of drug released was less. Verapamil partially reversed the multiple drug-resistance phenotype by increasing the initial rate of uptake and accumulation of drugs in the resistant cell lines without an apparent effect on drug efflux. The results suggest that, in this human epithelial cell, the development of resistance to multiple drugs is complex, with changes in drug uptake, accumulation, and efflux.

[The concentration of ceftizoxime in serum and lung tissues and prophylaxis of postoperative infections]

There are few clinical reports about the concentration of ceftizoxime (CZX) in lung tissues. At present, clinically, we report the concentration of the drug in serum and lung tissues on 26 cases of chest disease and an effect of the drug on prophylaxis of postoperative pulmonary infections. Our results are the following; The peak concentration of CZX in serum is 54.7 micrograms/ml at 1 hour after starting drip infusion of CZX 1 g. The serum half-life of CZX (beta phase) is 2.07 hours. The concentration of CZX in lung tissues is from 43.6 to 78.7% of serum level. CZX is useful to prophylaxis of postoperative infections after thoracotomy, especially in case of administration of CZX 1 g just before operation. Eruption was found in 1 of 26 cases. However, no side effects of the drug are noticed in other 25 cases.

Defective endocytosis of low-density lipoprotein in monensin-resistant mutants of the mouse Balb/3T3 cell line

Two monensin-resistant clones show similar low-density lipoprotein binding activity but less internalization or degradation of low-density lipoprotein than the parental Balb/3T3 or other resistant clone. Sterol synthesis from radioactive acetate in the resistant mutant, MO-5, is inhibited by more than 70% of control in the presence of tenfold higher amounts of low-density lipoprotein than the dose that inhibits the parental Balb/3T3 to similar level. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity of Balb/3T3 and MO-5 is inhibited by 48% and 27% of control, respectively, in the presence of 10 micrograms/ml of low-density lipoprotein. Colloidal silica gradient centrifugation shows that transport of low-density lipoprotein from the surface membrane to the lysosome is much slower in MO-5 cells than in Balb/3T3 cells. Down regulation of low-density lipoprotein receptors on the cell surface in Balb/3T3 is observed by exposing the cells to 5-15 micrograms/ml low-density lipoprotein, whereas only slight if any down regulation is observed when MO-5 cells are treated with low-density lipoprotein. The altered endocytosis of low-density lipoprotein behaves as a dominant trait in hybrids of MO-5 and THO2-2, a derivative of Balb/3T3 resistant to both ouabain and 6-thioguanine.

Basal cell carcinoma with lung metastasis

A forty-seven year-old man had a small ulceration on his left cheek. The ulcer had a repeated crust formation following removal, for ten years. The patient found a hard tumor in the deep site of the ulcer and the tumor was resected. The pathological diagnosis was basal cell carcinoma. The metastases to the regional lymph nodes developed one year later and these lymph nodes were resected. The histological picture was the same as seen in the primary tumor. Lung metastasis occurred three years later. The tumor was resected and the pathological diagnosis was basal cell carcinoma. Multiple lung metastases developed one year later and massive hemoptysis led to a sudden death two years after the thoracotomy. Thirty-seven cases of basal cell carcinoma with lung metastases were reported in the literature. This case is the thirty-eighth case and the third occurrence in a Japanese.

The effect of calcium antagonists on the proteolytic degradation of low-density lipoprotein in HeLa cells

The degradation of 125I-labelled low-density lipoproteins (LDL) in HeLa cells was significantly inhibited when the cells were incubated either with the calcium channel blocking agents D600 and verapamil, or with the lysosomotropic agent chloroquine. However, nifedipine, another blocker of Ca2+ channels, did not affect the degradation of 125I-labelled LDL. The association of 125I-labelled LDL with HeLa cells was increased in proportion to the concentration of D600, and 125I-labelled LDL was accumulated in lysosomal fractions as assessed by Percoll density gradient analysis. Some 80% of 125I-labelled LDL in lysosomes of HeLa cells treated with D600 was acid-insoluble. The rate of incorporation of [3H]acetate into digitonin-precipitable material was increased 4-fold in the cells treated with 40 micrograms/ml D600 compared with untreated cells, but that of [3H]mevalonate was not enhanced. About 8 h of preincubation of the cells with D600 or verapamil was required to inhibit the LDL degradation by 50% of the control activity. It was also found that the inhibitory action of D600 could be reversed by removal of D600 from the medium. The activities of lysosomal enzymes, cathepsin B, beta-hexosaminidase, and acid phosphatase, were significantly decreased when the cells were treated with D600 and chloroquine, but not with nifedipine. Blockers of Ca2+ channels which effect the activity of lysosomal enzymes, should be useful for the study of the lysosomal function.

Potentiation by squalene of the cytotoxicity of anticancer agents against cultured mammalian cells and murine tumor

Squalene (SQ) was examined for ability to potentiate the cytotoxicity and antitumor activity of anticancer agents. The dose-response curves of cell survival of cultured HeLa or V79 cells in the presence of various anticancer agents [adriamycin (ADM), 5-fluorouracil (5-FU), bleomycin (BLM) and cis-dichlorodiamminoplatinum (CDDP)] showed that SQ potentiated the cytotoxicity of these anticancer agents. SQ may enhance the cytotoxic effect of ADM by interfering with the efflux of ADM from the cells. The antitumor activities of these anticancer agents combined with SQ were tested against sarcoma 180 (S180) ascites cells. Some combinations were found to show synergistic antitumor effects: ADM, BLM or CDDP with SQ was effective against S180, but only slight if any synergistic effect was observed with the combination of 5-FU and SQ. The antitumor activity of BLM was most strongly potentiated by SQ, among the tested agents.

[Analysis of cell surface antigens of gastric cancer and preliminary study of clinical application by using mouse monoclonal antibodies produced against NUGC3]

Four monoclonal antibodies (GC301, 302, 303, 304) produced by hybridomas obtained from mice immunized with NUGC3 were analyzed by serological assay (Mixed Hemadsorption Assay-MHA) and immunoperoxidase technique. GC301(IgG1) showed tumor restricted reactivity in serological analysis, but it reacted with fibrous interstitial tissues immunohistochemically. GC302(IgG1) was serologically reactive with epithelial tumors such as gastric cancers, colon cancers and gynecological cancers, but not with brain tumors, melanomas and other normal cells. In tissue sections, all gastric cancers, intestinal metaplasia, stomach of fetus and bile duct were stained, but brain and hepatocytes were not. These results indicate that the antigen detected by GC302 is not only differentiation antigen by which gastrointestinal tract could be divided into foregut and midgut origins, but also the new type of oncofetal antigen different from CEA. GC302 would be useful for preoperative detection of gastric cancer in lymph nodes, using radioimmunodetection scans. GC303(IgG1) and GC304(IgG1) were broadly reactive with various cells in serological assay. Immunohistochemically, GC304 reacted with submucosal connective tissue, which was inhibited by collagenase. The results obtained from GC301 and GC304 suggest the possibility of interaction between tumor cells and interstitial tissues.

Multiply drug-resistant human KB carcinoma cells have decreased amounts of a 75-kDa and a 72-kDa glycoprotein

Human KB carcinoma cells were selected in sequential steps for resistance to colchicine and found to be cross-resistant to multiple drugs, including vinblastine, adriamycin, and actinomycin D. Compared with the parental line, the multiply resistant cells have decreased amounts of two [35S]methionine-labeled proteins with apparent molecular masses of 75 and 72 kDa. These proteins reappear in a revertant, drug-sensitive cell line. Both proteins are labeled with [14C]glucosamine and are retained on a wheat germ agglutinin-agarose column, indicating that they are glycoproteins. These data suggest that in this human cell line, these two glycoproteins can serve as a marker of the multiple drug-resistance phenotype and may play a role in its etiology.

Isolation and genetic characterization of human KB cell lines resistant to multiple drugs

Human KB cell lines resistant to high levels of colchicine were isolated by several successive single-step selections. Most of these selection steps resulted in cross-resistance to vincristine, vinblastine, adriamycin, actinomycin D, and puromycin; however, at the highest levels of colchicine resistance, increased cross-resistance to other drugs was not observed. There was no major change in protein synthesis or alteration in protein phosphorylation or [14C]glucosamine labeling patterns accompanying the development of multiple drug resistance as measured by analysis of metabolically labeled proteins on SDS gels. Cell-cell hybridization experiments showed that the colchicine-resistant and multiple drug-resistant phenotypes were incompletely dominant. In addition, colchicine resistance was found to segregate independently from resistance to other drugs in one somatic cell hybrid, suggesting that complex genetic loci are involved in the development of the multiple drug-resistant phenotype. These mutants should be useful for the study of the clinically important problem of multiple drug resistance in human cancer.

[The effect of calcium antagonists on intracellular transport of epidermal growth factor and the conjugate of epidermal growth factor with pseudomonas exotoxin]

Calcium antagonists, verapamil and D600, enhance the toxicity of EGF-PE and anti-TFR-PE. EGF and EGF-PE are accumulated in their intact form in the lysosomes of cells treated with D600 or verapamil. Verapamil and D600 decrease the activity of lysosomal enzymes, especially of cathepsin B. Verapamil may enhance the cytotoxicity of EGF-PE by blocking lysosomal degradation of EGF-PE.

Potentiation of cytotoxic activity of immunotoxins on cultured human cells

The cytotoxic activity against human tumor cells of toxic conjugates of Pseudomonas exotoxin with anti-transferrin receptor antibody or epidermal growth factor was potentiated up to 10 to 20-fold by the calcium antagonists verapamil, D-600, and diltiazem and by the lysosomotropic agent beta-glycylphenyl-naphthylamide. The potentiating activity of these agents could be predicted by measuring the inhibition of protein synthesis by the immunotoxins on various cell lines. The use of potentiating agents such as these in combination with immunotoxins may prove useful in the treatment of some human cancers.

An assessment of overall open-loop "gain" of CO2-ventilation feedback control system in hypoxia

Overall open-loop gain of the CO2-ventilation feedback control system in hypoxia (GHCO2) was determined on 8 male and one female healthy subjects. They breathed in a closed circuit, and were subjected to the progressive hypoxia test. This procedure was first conducted without dead space (DS), then with 250, 500, and finally 750 ml DS, consecutively. GHCO2 was calculated by dividing the slope of the CO2 response curve (S) by that of the metabolic hyperbola (SL). GHCO2 was considerably larger than the overall open-loop gain of the O2-ventilation feedback control system (GO2) previously obtained. This was ascribed to the facts that S was larger than the slope of the hypoxia response curve, and that the absolute value of SL in GHCO2 was smaller than that in GO2.

Potentiation of anticancer agents by new synthetic isoprenoids. II. Inhibition of the growth of transplantable murine tumors

The antitumor effects of combinations of synthetic isoprenoids-decaprenylamine.HCl, N-(p-methylbenzyl)decaprenylamine.HCl [N-(PMB)-decaprenylamine.HCl], and decaprenoic acid-with anticancer agents were studied in male ICR mice with ascites sarcoma 180 (S180) and in male BALB/c mice with fibrosarcoma Meth A. Decaprenylamine.HCl, N-(PMB)-decaprenylamine.HCl, and decaprenoic acid were tested in combination with bleomycin A2 (BLM) on S180. Decaprenoic acid was also examined in combination with BLM or 5-fluorouracil (FUra) for effects on fibrosarcoma Meth A. The dosages of synthetic isoprenoids used in the combination therapy were much below the median lethal dose. In the low-dosage schedule, decaprenylamine.HCl, N-(PMB)-decaprenylamine.HCl or decaprenoic acid considerably enhanced the antitumor effect of BLM on S180; e.g., the T/C value (mean survival time of treated mice/mean survival time of controls) for decaprenylamineHCl plus BLM, N-(PMB)-decaprenylamine.HCl plus BLM, or decaprenoic acid plus BLM was 294, 357, and 279% respectively, and the combinations increased life-span 2.4-fold, 2.3-fold, or 1.8-fold, respectively, as compared to the effects of BLM alone. The combination of BLM or FUra with decaprenoic acid, when administered by iv injection to mice with fibrosarcoma Meth A (solid tumor system), did not produce synergism. However, a preventive effect of decaprenoic acid monotherapy was observed: Decaprenoic acid at 3 mg/kg resulted in 38.9% suppression of tumor growth 21 days after inoculation.

Verapamil enhances the toxicity of conjugates of epidermal growth factor with Pseudomonas exotoxin and antitransferrin receptor with Pseudomonas exotoxin

Verapamil, a clinically important calcium channel blocker, has been found to cause a 40-fold enhancement of killing of the human KB cell line by a cytotoxic conjugate of epidermal growth factor with Pseudomonas exotoxin (EGF-PE). Synergistic effects of verapamil and EGF-PE are also seen on HeLa D98 cells and a human epidermal carcinoma cell line, A431. Verapamil also potentiates the effect of a toxic conjugate formed between Pseudomonas exotoxin and a monoclonal antibody to the human transferrin receptor (anti-TFR-PE) and enhances the effect of Pseudomonas exotoxin (PE) alone. Two other calcium antagonists were tested. Diltiazem enhances the cytotoxic effect of EGF-PE, but nifedipine does not. Verapamil does not affect the binding and uptake of 125I-EGF by KB cells, but it significantly delays the disappearance of internalized 125I-EGF from the cells. Density gradient fractionation studies using cell homogenates suggest that 125I-EGF accumulates in an undegraded form in lysosomes when cells are treated with verapamil. By immunofluorescence microscopy using an antibody to PE, EGF-PE was found to accumulate in lysosomes; by electron microscopy the lysosomes had an abnormal appearance. The effects of verapamil on toxicity of EGF-PE and lysosomal function appear to be related. However, it is not known whether the enhanced toxicity of EGF-PE in the presence of verapamil is due to its delayed degradation in lysosomes or some more general effect of verapamil on membrane permeability.

Imidazole-resistant phenotype and virus transformation in cultured rat cells

Compared to an untransformed rat cell line, 3Y1, adenovirus 12-transformed cell lines of 3Y1 were highly sensitive to the cytotoxic action of an imidazole antibiotic, clotrimazole. In contrast, SV40-transformed rat cell lines derived from the 3Y1 cell line showed no appreciable difference in the response to clotrimazole when compared to 3Y1 cells. Clotrimazole-resistant clones, WCT-1 and WCT-2, which were spontaneously isolated from the adenovirus 12-transformed cell line W5, showed 5- to 10-fold higher resistance than did W5; the dose-response curves of clotrimazole-resistant clones were similar to those of the untransformed 3Y1 cells. The growth of 3Y1 cells was blocked in the presence of 1% serum, whereas those of W5, WCT-1, and WCT-2 cells were only slightly affected by the same dose of serum in the medium. The membrane fractions of 3Y1, W5, and WCT-1 cells were found to contain similar cholesterol:phospholipid ratios. The phospholipid composition in the membrane fraction of line WCT-1 was similar to that of line W5 but not to that of line 3Y1. By contrast, the fatty acid composition was specifically altered in clotrimazole-resistant clones; cellular contents and some species of fatty acid such as 16:1, 18:2, and 20:4 in WCT-1 and WCT-2 cells were similar to those of 3Y1 but not to those of W5 cells. Differential sensitivities of various cell lines to clotrimazole are discussed in relation to the lipid composition.