Relationship between tumor histopathology and in vitro sensitivity to antitumor drugs in gastric cancer

The in vitro drug sensitivity of gastric cancer tissues obtained from 40 patients with advanced cancer was compared in terms of the pathological classifications which were assigned according to the General Rules for the Gastric Cancer Study in Surgery and Pathology in Japan. Cases of poorly differentiated adenocarcinoma which had penetrated the serosa were evaluated using the succinate dehydrogenase inhibition (SDI) test for determining the in vitro chemosensitivity. The sensitivity of the stage III group to cisplatin was higher than that of the stage IV group. Although there were no statistical differences in drug sensitivities according to macroscopic findings (Borrmann's classification), the expanding growth type was more susceptible that the infiltrating type to cisplatin, aclacinomycin A (ACR) and carboquone (CQ) microscopically. In cases of lymph node metastasis [n(+)] the sensitivity to cisplatin, ACR, CQ, adriamycin and mitomycin C was less than in those with or without primary lymph node metastasis [n(-)]; lymphatic invasion in the gastric wall (ly) was a significant factor linked to drug resistance. Our findings indicate that the evaluation of tumor pathology is important in predicting the chemosensitivity of poorly differentiated gastric cancers.

5-Fluorouracil's cytotoxicity is enhanced both in vitro and in vivo by concomitant treatment with hyperthermia and dipyridamole

We obtained evidence that the cytotoxic effect of 5-fluorouracil (5-FU) is augmented when the drug is given in combination with hyperthermia (HYP) and dipyridamole (DP). Nontoxic levels of DP enhanced the combined cytotoxicity of 5-FU and HYP against B16 melanoma and human tumor cells in vitro as measured by the succinate dehydrogenase inhibition (SDI) test. Growth of B16 melanoma that had been subcutaneously implanted into the feet of C57 BL mice was inhibited by treatment with the combinations of 5-FU and HYP, of 5-FU and DP, and of 5-FU, HYP and DP as compared with the administration of 5-FU alone. Treatment with HYP plus DP did not alter the body weight of mice that received 5-FU. The administration of DP plus HYP seemed to render the tumor cells more sensitive to 5-FU. The combination of 5-FU, HYP and DP shows promise for the treatment of patients suffering from malignant disease.

Dipyridamole augments the antitumor effects of fluorinated pyrimidines

The antitumor effects of 5-fluorouracil (5-FU) and its analogues when combined with dipyridamole (DP) were investigated using B16 melanoma cells, in vitro and in vivo. First, the enhancement of 5-FU cytotoxicity by DP was examined in vitro. Cell growth was suppressed significantly by combining 5-FU and a nontoxic dose of DP (2.5 micrograms/ml) as compared to 5-FU alone. Next, the effect of DP was examined in vivo in combination with 5-FU, tegafur (FT) and UFT. UFT had the most remarkable antitumor effect when given in a single equimolar dose. Although DP alone did not affect tumor growth, the growth inhibition by antitumor drugs was augmented by DP. DP enhanced the antitumor effect of UFT significantly (P less than 0.05), and combination treatment with UFT and DP proved to be the most effective regimen for inhibiting growth of B16 melanoma. Combination treatment with UFT and DP shows promise for clinical cancer.

Simultaneous adenocarcinoma of the stomach and fourth portion of the duodenum: case report and review of the literature

We treated a woman with simultaneous adenocarcinoma of the stomach and fourth portion of the duodenum. She complained of symptoms of obstruction in the duodenum, and both lesions were correctly diagnosed, preoperatively. Noncurative resection was done because of distant lymph node metastasis. The new adjuvant chemotherapy using THP-adriamycin and UFT was prescribed, and one year after surgery she remains in recession.

Dipyridamole potentiates adriamycin cytotoxicity by a mechanism other than inhibiting nucleoside uptake

Nitrobenzylthioinosine (NBTI) and dipyridamole (DP) are competitive inhibitors of cellular nucleoside uptake. Although combined treatment of HeLa cells with adriamycin (ADM) and DP enhanced ADM cytotoxicity in cell growth and clonogenic assays, the combination of ADM and noncytostatic levels (less than 1 microM) of NBTI did not change the cytotoxic potential of ADM in vitro. DP enhanced the inhibition of clonogenicity by ADM, even in nucleoside-enriched mediums. These results suggest that the synergy between ADM and DP was hardly due to the inhibition of nucleoside uptake by DP, but was due to the enhancement of intracellular ADM accumulation by DP.

Modulation of cytotoxic effect of anticancer drugs by dipyridamole in HeLa cells in vitro

Exponentially growing HeLa cells were treated with various antitumor drugs and dipyridamole (DP), and the cell growth inhibition ratio was determined. Enhanced growth inhibition was found in combined treatment with DP and 5-fluorouracil, 1-hexylcarbamoyl-5-fluorouracil, methotrexate, adriamycin, daunomycin, 4'-0-tetrahydropyranyl-adriamycin, actinomycin D and vincristine. In contrast, reduction of the cytotoxic effect of cytosine arabinoside and enocitabine was found when these were combined with DP.

Bovine plasma protein C inhibitor with structural and functional homologous properties to human plasma protein C inhibitor

Bovine plasma protein C inhibitor was purified; it was then characterized in comparison with human protein C inhibitor. The specific inhibitory activity of the purified inhibitor for bovine activated protein C was 8,500 times that of the inhibitor in plasma. The purified inhibitor showed a single band with Mr 56,000 by SDS-PAGE at pH 7.0, and two bands at pH 8.8, a major one with Mr 56,000 and a minor one with Mr 105,000, under both unreduced and reduced conditions. The pI range of the inhibitor was between 4.4 and 6.1. The Mr of the inhibitor was reduced by treatment with neuraminidase, O-glycanase, and also with glycopeptidase-A, suggesting that the inhibitor has both Asn-linked and Ser/Thr-linked carbohydrate chains. Twenty-seven of the NH2-terminal 49 amino acid residues of the bovine inhibitor, which lacks the first 4 residues from the NH2-terminal amino acid sequence of human inhibitor, were identical to those of the human inhibitor. The bovine inhibitor inhibited bovine and human activated protein C, human thrombin, Factor Xa, Factor XIa, and plasma kallikrein with Ki = 1.0, 5.2, 2.6, 3.0, 1.3 X 10(-8) M, and 4.5 X 10(-9) M, respectively. The inhibitory rates for activated protein C and thrombin were accelerated significantly in the presence of heparin or negatively charged dextran sulfate. However, the acceleration by heparin or dextran sulfate for the inhibition of Factor Xa, Factor XIa, and plasma kallikrein was not significant. The bovine inhibitor did not inhibit human Factor XIIa or plasmin.(ABSTRACT TRUNCATED AT 250 WORDS)

Species differences in substrate specificity of pyrimidine nucleoside phosphorylase

To compare the activity of pyrimidine nucleoside phosphorylase (PNP), an enzyme involved in the metabolism of 5-fluorouracil (5-FU), we used uridine (Urd), deoxyuridine (dUrd), and thymidine (dThd) as substrates and human, rat, and mouse neoplastic and normal tissues. As PNP activity was higher in the tumor tissues than in the normal ones in all species examined, the level of PNP activity is expected to be one critical factor linked to the effectiveness of 5-FU. In rats and mice, the ratio of the activities of Urd, dUrd, and dThd was about 10:7:1, whereas in humans, the ratio was 1:30:20. The main enzyme of PNP is Urd phosphorylase in rodents and dThd phosphorylase in humans. Therefore, when examining the metabolism of 5-FU and its analogues for potential clinical application, human tissues should be used.

Azo-dye-induced primary hepatoma and a gradual increase in thermosensitivity

To determine whether or not the cytotoxic effects of hyperthermia are directed primarily to malignant cells, we examined changes in thermosensitivity during hepatocarcinogenesis in rats, as induced by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). The findings were compared with those in livers of rats fed a commercial diet. The cell viability was determined using the succinate dehydrogenase inhibition (SDI) test. The succinate dehydrogenase (SD) activity of liver cells, when exposed to heat (43 degrees C) for 2, 5, or 10 hr, decreased in a time-dependent manner, in each tissue. The decrease in SD activity was evident in 3'-Me-DAB liver for 5 hr of heat treatment on day 57, compared with findings in the normal liver. Significant differences were present for 2, 5, and 10 hr on days 93 and 136. Thus a chemically induced hepatoma is more sensitive to heat than are the normal cells. As this thermosensitivity gradually increased during the hepatocarcinogenesis, the malignant cells are particularly vulnerable to hyperthermia.

Potentiation of 5-fluorouracil cytotoxicity by combining hyperthermia and dipyridamole in vitro

Evidence was obtained for the augmentation of cytotoxic effects of 5-fluorouracil (5-FU) when hyperthermia and dipyridamole (DP) were combined in vitro. Nontoxic levels of DP enhanced the combined cytotoxicity of 5-FU and heat against HeLa and B16 melanoma cells, and the 50% effective concentration of 5-FU decreased 7.3 fold for HeLa cells and 3.0 fold for B16 melanoma cells, when exposed to heat plus DP. This combined effect did not depend on intracellular increases in the concentrations of 5-FU. Thus hyperthermia together with DP seems to improve the sensitivity of tumor cells to 5-FU. As the sensitivity of colorectal cancer tissue to drugs is low, 5-FU plus hyperthermia and DP shows promise for the treatment of such patients.

5-Fluorouracil and UFT-sensitive gastric carcinoma has a high level of thymidylate synthase

The authors examined the relationship between the level of thymidylate synthase (TS) and the sensitivity to 5-fluorouracil (5-FU) and UFT, a combined oral preparation of 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur) and uracil in a molar ratio of 1:4. For the studies we used the subrenal capsule (SRC) assay and 15 human gastric cancer tissues. The TS levels were assayed by the ligand-binding technique, using [6-3H]FdUMP. The relative variation of tumor size (delta TuS/TuS0) was calculated to be as follows: delta TuS/TuS0 = [(TuS6 - TuS0)/TuS0] x 100 (%), where TuS6 was the tumor size on day 6 and TuS0 on day 0. The chemosensitivity was considered to be positive when delta TuS/TuS0 in the treated group decreased to below -10%. Decrease in tumor size was marked in case of exposure to UFT (-19.8 +/- 13.0%) (mean +/- standard deviation), compared with that to 5-FU (-9.0 +/- 7.2%), with a statistically significant difference (P less than 0.001). The TS level varied from 1.7 to 30.8 pmol/g gastric cancer tissue and the mean was 7.1 +/- 7.2 pmol/g tissue. A correlation was noted between the TS level and decrease in size of the tumor exposed to 5-FU (r = -0.671) or UFT (r = -0.758): gastric cancer tissue with higher level of TS is more sensitive to 5-FU and UFT than is that with a lower TS level. These findings show that the sensitivity to 5-FU and UFT of gastric cancer tissue is related to the TS level and that UFT shows promise for the treatment of patients with gastric cancer.

4'-O-tetrahydropyranyladriamycin has greater antineoplastic activity than adriamycin in various human tumours in vitro

The sensitivities of 84 human tumor tissues (23 gastric, 8 colorectal cancers, 34 hepatomas, 6 breast, 6 lung cancers and 7 malignant lymphomas) to adriamycin (ADM) and 4'-0-tetrahydropyranyladriamycin (THP-ADM), a semisynthetic anthracycline glycoside, were determined using the in vitro succinate dehydrogenase inhibition (SDI) test. The succinate dehydrogenase (SD) activity of the tumor tissues was assayed following exposure to 6.9 microM of the drug for 3 days; sensitivity was considered positive when the SD activity decreased to below 50% of that of the control cells. In the case of exposure to THP-ADM, the SD activity in the tissue decreased and the decrease was more extensive in the gastric, colorectal cancers, hepatomas, lung cancers, with a statistically significant difference (P less than 0.001-P less than 0.05), but not in the breast cancers and malignant lymphomas. The rate of sensitivity was 70.2% for THP-ADM and 51.2% for ADM in the 84 tumor tissues. The percentage of tissues with a higher sensitivity to THP-ADM, compared to ADM, was 79.8%. As THP-ADM proved to be more cytotoxic than ADM to human tumors in vitro, this drug should be kept in mind when anti-cancer chemotherapy is designed.

In vitro sensitivity of various human tumors to 1-beta-D-arabinofuranosylcytosine and N4-behenoyl-1-beta-D-arabinofuranosylcytosine

The sensitivities to 1-beta-D-arabinofuranosylcytosine (ara-C) and N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC), a masked compound of ara-C, were determined in 33 human tumor tissues (11 gastric, 6 colorectal cancers and 16 malignant lymphomas), using the in vitro succinate dehydrogenase inhibition test. The succinate dehydrogenase (SD) activity of the tumor tissues was assayed following exposure to the drug at 8.8 or 88 microM for 3 days and the sensitivity was considered positive when the SD activity decreased to below 50% of that of the control cells at 88 microM. The SD activity decreased little at 8.8 microM and decreased individually at 88 microM. The mean of the SD activity at 88 microM was 65.7 +/- 11.5% for ara-C and 61.4 +/- 14.5% for BH-AC in gastrointestinal cancers, and 63.8 +/- 16.0% for ara-C and 58.3 +/- 18.3% for BH-AC in malignant lymphomas with a statistically significant difference (p less than 0.05). BH-AC is converted to ara-C for exertion of the cytotoxic effect and a positive correlation was noted between the SD activities of ara-C and BH-AC (r = 0.825 at 88 microM). The chemosensitivity varied with the tissue and 18% of the tissues were sensitive to ara-C, 27% to BH-AC and 15% were sensitive to BH-AC but resistant to ara-C. Our findings show that ara-C and BH-AC are equally cytostatic to human tumors. The sensitivity test of ara-C and BH-AC enables one to determine which drug is best suited for individual patients.

Pyrimidine nucleotide synthesis is more extensive in poorly differentiated than in well-differentiated human gastric carcinoma

In tissues obtained from patients undergoing gastrectomy, the activities of 12 enzymes involved in pyrimidine nucleotide synthesis: cytidine triphosphate (CTP) synthetase, deoxycytidine monophosphate (dCMP) deaminase, thymidine monophosphate (dTMP) kinase, uridine (Urd), deoxycytidine (dCyd) and thymidine (dThd) kinases, Urd, deoxyuridine (dUrd) and dThd phosphorylases, cytidine (Cyd) and dCyd deaminases, and DNA polymerase were examined in the eight-well-differentiated and 12 poorly differentiated gastric cancer tissues and the ten normal tissues. These cases were clinically advanced and serosal invasions were evident. Activities of these enzymes were higher in the poorly differentiated tissues than the well differentiated type and in the normal tissues. Significant differences were noted between the poorly differentiated and well-differentiated types, in dTMP kinase (P less than 0.02), dThd kinase (P less than 0.05), dThd phosphorylase (P less than 0.01), and DNA polymerase (P less than 0.05). The authors' findings show that the level of pyrimidine nucleotide synthesis, in both de novo and salvage pathways, is higher in the poorly differentiated gastric cancer tissues than in the well-differentiated type and suggest that antitumor drugs have an increased susceptibility in cases of poorly differentiated gastric carcinoma.

Cytotoxicity of N4-behenoyl-1-beta-D-arabinofuranosylcytosine through gradual conversion to 1-beta-D-arabinofuranosylcytosine in HeLa cells

The metabolism of 1-beta-D-arabinofuranosylcytosine (ara-C) and N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC) was studied in Hela cells. After the cells were exposed to ara-C at a concentration of 20 micrograms/ml or BH-AC at 46.5 micrograms/ml for 1, 3, 6, 12 or 24 hr, the level of ara-C was determined using the radioimmunoassay method, and the level of BH-AC and 1-beta-D-arabinofuranosyluracil (ara-U), using high-performance liquid chromatography. In the ara-C-treated cells, the intracellular ara-C increased to 1.26 micrograms/g cells after exposure for 6 hr, and ara-C was rapidly changed to ara-U in the cells and in the medium. In the BH-AC-treated cells, the intracellular BH-AC increased after exposure for 24 hr and BH-AC was gradually converted to ara-C in the cells: the intracellular level of ara-C was only 15% of that of BH-AC after exposure for 24 hr. BH-AC level in the medium persisted for 24 hr, at the initial concentration. Our findings show that BH-AC is stable compared to ara-C and gradually converts to ara-C. This conversion is presumably a critical step in the antineoplastic effect of BH-AC.

Tumor tissue is more sensitive to mitomycin C, carboquone, and aclacinomycin A than is adjacent normal tissue in vitro

In tissues obtained from patients undergoing gastrectomy or colectomy, sensitivity to mitomycin C (MMC), carboquone (CQ), and aclacinomycin A (ACR) was examined in 20 tumors (15 gastric, 5 colorectal) and in the adjacent normal mucosal tissues, using the in vitro succinate dehydrogenase inhibition test. The succinate dehydrogenase (SD) activity decreased to a greater extent in the tumor tissues than in adjacent normal tissues, at rates of 80% for MMC, 80% for CQ, and 90% for ACR. There were no correlations between SD activities of tumor and adjacent normal tissue, r = 0.157 for MMC, r = 0.435 for CQ, and r = 0.375 for ACR. Normal tissues were sensitive to MMC in 25% of cases sensitive to MMC in the tumor tissues, 46% for CQ, and 38% for ACR. These results show that the antitumor effects of MMC, CQ, and ACR are relatively specific for tumor tissues and that the assay of chemosensitivity of normal tissues is meaningful for predicting the toxic effects of antitumor drugs on these tissues.

Chemosensitivity differences between primary and metastatic lesions of clinical gastric cancer

An in vitro chemosensitivity test, the succinate dehydrogenase inhibition (SDI) test, was used to examine 16 pairs of samples obtained simultaneously from primary and metastatic lesions of clinical gastric cancer. Concerning the metastases, 11 were in the lymph nodes and five in the liver. The chemosensitivities of metastatic lesions against six anti-tumour drugs, carboquone (CQ), adriamycin (ADM), mitomycin C (MMC), aclacinomycin A (ACR), and 5-fluorouracil (5-FU), differed from those in the primary lesions, and there were no correlations of chemosensitivities between the primary and the metastatic lesions against these drugs, except for DDP. The lymph nodes were more sensitive to CQ, ADM, MMC, DDP, ACR and 5-FU, while the liver was less sensitive than the primary lesions to CQ, ADM, MMC, DDP, and ACR. Our findings indicate that in patients with lymph node metastasis, there is a sensitivity to anti-tumour drugs, while in cases of liver metastasis, drug treatment may be less effective. We propose that chemosensitivity testing should be done when attempting to design anti-tumour drugs.

Human genes for complement components C1r and C1s in a close tail-to-tail arrangement

Complementary DNA clones for human C1s were isolated from cDNA libraries that were prepared with poly(A)+ RNAs of human liver and HepG2 cells. A clone with the largest cDNA insert of 2664 base pairs (bp) was analyzed for its complete nucleotide sequence. It contained 202 bp of a 5' untranslated region, 45 bp of coding for a signal peptide (15 amino acid residues), 2019 bp for complement component C1s zymogen (673 amino acid residues), 378 bp for a 3' untranslated region, a stop codon, and 17 bp of a poly(A) tail. The amino acid sequence of C1s was 40.5% identical to that of C1r, with excellent matches of tentative disulfide bond locations conserving the overall domain structure of C1r. DNA blotting and sequencing analyses of genomic DNA and of an isolated genomic DNA clone clearly showed that the human genes for C1r and C1s are closely located in a "tail-to-tail" arrangement at a distance of about 9.5 kilobases. Furthermore, RNA blot analyses showed that both C1r and C1s genes are primarily expressed in liver, whereas most other tissues expressed both C1r and C1s genes at much lower levels (less than 10% of that in liver). Multiple molecular sizes of specific mRNAs were observed in the RNA blot analyses for both C1r and C1s, indicating that alternative RNA processing(s), likely an alternative polyadenylylation, might take place for both genes.

Potentiation of adriamycin cytotoxicity by dipyridamole against HeLa cells in vitro and sarcoma 180 cells in vivo

Dipyridamole (DP) is clinically prescribed for its vasodilating and antiplatelet effects. DP also inhibits nucleoside transport and enhances cytostatic activity of antimetabolites. We obtained evidence for augmentation of the cytocidal effect of Adriamycin (ADM) by DP, both in vitro and in vivo. Nontoxic levels of DP enhanced the cytotoxicity of ADM against HeLa cells, and the 50% effective concentration of ADM was decreased 2.4-fold by DP. DP also increased the activity of ADM in clonogenic assays. Intracellular levels of ADM in the case of concomitant exposure to ADM and DP were 1.5-fold higher than in the case of exposure to ADM alone, determined using high-performance liquid chromatography. Incorporation of ADM into the cells pretreated with DP was also increased (1.4-fold), while the efflux was little affected. The growth of Sarcoma 180 tumors was prominently suppressed by the combination of ADM and DP, compared to findings with ADM alone. DP also prolonged the survival of Sarcoma 180 tumor-bearing mice, when given in combination with ADM. While the enhancement of cytostatic activity of antimetabolites has been attributed to a decrease in utilization of the salvage pathway by DP, our data show that the synergic effects of DP with ADM were the result of increased intracellular levels of ADM.

Gene structure of human thrombomodulin, a cofactor for thrombin-catalyzed activation of protein C

The gene coding for human thrombomodulin, a thrombin receptor on endothelial cells and a cofactor for the activation of anticoagulant protein C zymogen, was isolated from a human genomic library by employing human thrombomodulin cDNA as a probe. The nucleotide sequences of the gene and the adjacent 5' and 3' flanking regions were then determined. The nucleotide sequence of this gene with approximately 3.7 kilobase pairs was identical to that of the cDNA, indicating that the gene for human thrombomodulin is free of introns. Hybridization data showed that there is only a single thrombomodulin gene in the human genome.

[Human colorectal carcinoma is more sensitive to HCFU than 5-FU and tegafur in in vitro and in vivo drug sensitivity tests]

The sensitivity of human colorectal cancer to 5-fluorouracil (5-FU) and its derivatives: 1-(tetrahydro-2-furyl)-5-FU (tegafur) and 1-hexylcarbamoyl-5-FU (HCFU) was determined by in vitro succinate dehydrogenase inhibition (SDI) test and in vivo subrenal capsule (SRC) assay. Using the SDI test with 25 colorectal cancer specimens, the succinate dehydrogenase (SD) activity decreased to 73.6 +/- 17.8% for 5-FU-treated cells and 37.2 +/- 17.0% for HCFU-treated cells, compared to that of control cells. The chemosensitivity-positive rates were 16% for 5-FU and 68% for HCFU. Using the SRC assay with 7 colorectal cancer specimens, the relative variation of tumor size, which was calculated by delta TS/TS0 = (TS6-TS0)/TS0 X 100 (%), decreased to -12.6 +/- 10.1% for 5-FU, -14.9 +/- 12.4% for tegafur and -23.9 +/- 14.2% for HCFU, and the inhibition of tumor growth following exposure to HCFU was evident. The chemosensitivity-positive rates were 49% for 5-FU, 57% for tegafur and 71% for HCFU. Our results show that HCFU is more effective to colorectal cancer than 5-FU and FT-207, and the chemosensitivity test of HCFU will be useful in determining the effective drug for the treatment of colorectal cancer.

Excised human neoplastic tissues are more sensitive to heat than the adjacent normal tissues

In tissues from patients subjected to gastrectomy or colectomy, the heat sensitivity was determined in the case of 23 neoplastic, 15 gastric, 8 colorectal, and the adjacent normal tissues, using the in vitro succinate dehydrogenase inhibition test. The succinate dehydrogenase (SD) activity of tissue fragments was assayed, following exposure to heat at 43 degrees C (heat treatment) or 37 degrees C (control) for 5, 10, 15 or 20 h. The sensitivity to heat treatment was estimated by the percentage of SD activity of the heat-treated cells, compared to that of control cells. The decrease in SD activity varied in the tumor tissue, following exposure to heat. The SD activity decreased to a greater extent in the tumor tissue than in the adjacent normal tissue, in each case. The mean +/- standard deviation of SD activity, following exposure to heat treatment for 20 h, was 32.1 +/- 14.0% for the tumour tissues and 52.4 +/- 10.4% for the adjacent normal tissues, with a statistically significant difference (p less than 0.01). These results show that the assay of heat sensitivity is meaningful for prediciting the effectiveness of hyperthermia and that hyperthermia has a selectivity for treating a malignant lesion.

New cytoskeletal proteins are induced in HeLa cells by Vinca alkaloids

The effects of Vinca alkaloids, vinblastine, vincristine, and vindesine, on protein synthesis were determined using HeLa cells. Vinblastine at the concentration of 1 microgram/ml induced new proteins, isoelectric points 4.8 and 7.0-7.5 and molecular weights 48 and 92 kd, in the HeLa cells, identified using two-dimensional gel electrophoresis. The 48-kd and the clustered (4-components) 92-kd proteins were also noted in HeLa cells treated with vincristine or vindesine. As most of the 48- and 92-kd proteins were Triton insoluble, they can be considered components of the cytoskeletal structure. Syntheses of these proteins were blocked by actinomycin D, therefore, new messenger RNA synthesis is required for induction. These proteins were not induced by an alkylating agent, antitumor antibiotics, or an antimetabolite. Our findings show that the 48- and the clustered 92-kd proteins are Vinca alkaloid reactive components and can be considered candidates for the elucidation of the antineoplastic effect of Vinca alkaloids.

Sensitivity test for 5-fluorouracil and its analogues, 1-(2-tetrahydrofuryl)-5-fluorouracil, uracil/1-(2-tetrahydrofuryl)-5-fluorouracil (4:1) and 1-hexylcarbamoyl-5-fluorouracil, using the subrenal capsule assay

The chemosensitivity of 20 human neoplastic tissues including 13 gastric and 7 colorectal cancers was tested using 5-fluorouracil (5-FU) and its analogues: 1-(2-tetrahydrofuryl)-5-FU (FT), uracil/FT (UFT) and 1-hexylcarbamoyl-5-FU (HCFU), and the in vivo subrenal capsule (SRC) assay. The relative variation of tumor size (delta TS/TSo) was calculated as follows: delta TS/TS0 = (TS6-TS0/TS0) x 100%, where TS6 was the tumor size on day 6 and TS0 on day 0, and the chemosensitivity was considered to be sensitive when delta TS/TS0 in the treated group was decreased to below -10%. The mean tumor size was -10.9 +/- (SD) 10.9% for 5-FU, -12.3 +/- 17.1% for FT, -18.4 +/- 15.8% for UFT and -17.9 +/- 15.4% for HCFU. The decrease of tumor size was marked when exposed to UFT (p less than 0.01) or HCFU (p less than 0.02), compared with that to 5-FU. Positive correlations were noted between the tumor sizes of 5-FU and its analogues (5-FU vs. FT, r = 0.851; 5-FU vs. UFT, r = 0.746; 5-FU vs. HCFU, r = 0.685). In 9 tissues resistant to 5-FU, 2 (22%) were sensitive to FT, 4 (44%) to UFT, 5 (56%) to HCFU and 7 tissues (78%) to at least one of these analogues. These results suggest that the SRC assay is useful for predicting the effective drug among 5-FU and 5-FU analogues, for individual patients with cancer.