Protein kinase C(PKC9 is a family of proteins with serine/threonine-specific protein kinase activity which is activated by diacylglycerol(DG)or tumor promot-ing phorbol esters such as TPA. PKC is the only substance identified so far as a cellular receptor for tumor promoting phorbol esters. Thus it is believed that PKC in one of the major component of intra-cellular signalling pathways and is involved in various cellular functions which are mimicked by phorbol esters. Recent molecular cloning and subsequent expression studies as well as biochemi-cal analysis of the PKC molecules revealed two major unexpected facts on the molecular nature of PKC and/or cellular phorbol ester receptor. One is that PKC (originally defined as Ca²⁺-, phospholipid-activated protein kinase by Nishizuka) is composed of four distinct molecular types, α, βI, βII, γ encoded by three distinct genes. These “conventional PKC molecules share similar enzymatic prop-erties which include substrate specificity and co-factor dependency of the kinase activity. Funthermore they confer phorbol ester receptor activity to intact cells when each cDNA was introduced into cells. The other unexpected fact we found is the presence of PKC-related proteins. PKC-related cDNAs encoded at least three additional members(“novel” PKC, nPKC δ, ε, and ζ) of the PKC family. These “novel” PKC molecules share only part of the sequences with “conventional”PKCs(Cys-rich repeat and kinase). nPKCε is a Ser/Thr-specific protein kinase which is activated by DG or phorbol esters. Furthermore nPKε serves as a phorbol ester receptor. These PKC and nPKC molecules are expressed in a cell-type specific manner, suggesting that they have distinct functional roles in cellular signalling pathways.

View full abstract

This paper describes a study about tissue distri-bution of localy injected a new dosage from(ACR-CH)of adarubicin(ACR) The new doseage form(ACR-CH), developed in order to distribute a greater amount of aclarubicin to regional lympy nodes, comprises 20 mg of polyvinylpyrolidone and 50 mg of small activated carbon particles adsorbing 5 mg/ml of ACR in saline. The particle size of activated carbon in the form of suspension is 167 μm on average. Aclar-ubicin at 5 mg/kg was injected subcutaneously into right forefoot-pad of rat in the form of ACR-CH or the ACR aqueous solution. The concentration of ACR in the tissues was measured upto 7 days after administration with high pressue liquid chromato-graphy method. Statistically, ACR concentration in the axillary lymph nodes of rats given ACR-CH was higher than 10 μg/g for 24 hours after adminis-tration and the value was significantly higher than that of rats given ACR aqueous solution. ACR concentration in blood and the other tissues(the heart, the lung, the spleen, the kidney)of rats given ACR-CH were statistically significantly lower than those of the rats given ACR aqueous solution. These results leads us to think that ACR-CH distributes a large amount of ACR into the regional lymph nodes and small amounts to the tissues of whole body.

View full abstract

We have attempted the overcoming of anticancer drug resistance in murine leukemia by unsaturated aliphatic compouns and investigated the drug up-take into cells using adriamycin(ADM)resistant mouse P 388 leukemia(P 388/ADM). When 150 μM unsaturated fatty acids such as oleic acid(OA, C18 : 1 Δ9), linoleic acid(LA, C18 : 2 Δ9-12)and α-linolenic acid(α-LNA, C18 : 3 Δ9-12-15)were added along with ADM to the P 388/ADM or ADM sensitive P 388 (P 388/S)culture in vitro, ADM resistance was greatly reduced, and especially α-LNA completely overcomed the resistance. In addi-tion, α-LNA showed a stronger its own killing activity to P 388/ADM than OA and LA. These fatty acids also potentiated the cytotoxicity of ADM against P 388/S. The uptake of ADM was increased by these fatty acids, however, large dif-ferences of enhancing rate at 3h were observed between P 388/S(2-7 fold)and P 388/ADM(16-30 fold). These findings suggest that unsaturated fatty acids can overcome ADM resistance in P 388 leuke-mia by enhancing the drug uptake and its own cell killing activity.

View full abstract

To obtain the maximal local anticancer effect with minimal systemic side effects, we prepared adriamycin(ADR)-containing poly(L-lactic acid) microspheres(ADR-MS)with an average diameter of 50 μm by the oil in oil emulsion method. An almost zero-order release of ADR from the ADR-MS was achieved in Tris buffer and ADR disappeared from the ADR-MS within 20 days. The treatment of mice bearing P 815 tumor cells with ADR-MS showed a higher survival rate than with free ADR. After the instillation of the ADR-MS into the pleural cavity of patients with pleuritis car-cinomatosa, ADR was detected in serum as well as in the pleural fluid for up to 15 days. Moreover, the amount of drainaged ADR was less than a few % of the administered dose, indicating that almost all the ADR-MS remained in the pleural cavity, ADR being released slowly. Furthermore, systemic side effects were not observed after the administration of the ADR-MS. The cytology of the pleural effusion indicated that the malignant stage became Class I after the instillation of the ADR-MS, inspite of adenocar-cinoma Class V before the treatment. The local administration of the ADR-MS was concluded to yield a maximal anticancer effect with minimal side effects.

View full abstract

Cis-diamminedichloroplatinum(CDDP)-contain-ing poly(lactic acid)microspheres(CDDP-MS)with an average diameter of 100 μm, prepared by the oil in oil emulsion method, released 60% of CDDP in Tris buffer within 24 hours. To improve the burst effect of the CDDP-MS, we prepared CDDP-containing poly(D, L-lactic acid) beads(CDDP-B)with a diameter of 2 mm. The CDDP-B showed a 2 phase releasing pattern. The first release was observed within 3 days and 40% of CDDP disappeared, while the second release was seen after 20 days and all of the CDDP disappeared until the day 30. When the CDDP-B was implanted in the femoral muscles of rabbits, peritoneal cavity of mice, and subcutaneous tissues of mice, CDDP was released almost continuously from the CDDP-B and disappeared within 2 to 3 weeks. CDDP was detected in serum for up to 3 weeks, when the CDDP-B was implanted in the peritoneal cavity, indicating slow release of CDDP from the CDDP-B. Histologically, the muscles which had been in contact with the CDDP-B, accompanied inflamma-tory cells and a small area of the necrosed tissue until 5 days and again at the day 14, but they disappeared at the day 7 and at the day 21. This histological change seens to be related to the 2 phase releasing pattern of CDDP from the CDDP-B in vitro.

View full abstract

A method to prepare cisplatin suspended in Lipiodol(LPS) has been established in order to deliver cisplatin to hepatocellular carcinoma via the hepatic artery. Ninety-six patients, two stage I, 20 stage II, 30 stage III, and 44 stage IV, were treated with LPS therapy. In 34 patients whose serum alpha-fetoprotein(AFP)levels were greater than 400 ng/ml, the serum AFP levels decreased in 31 patients(91.2%). The plasma des-γ-carboxy prothrombin(DCP)levels decreased in all of the 26 DCP-positive patients. The 1-year survival rate was estimated to be 60.4% and the 2-year survival rate was 42.7%. The patients treated with LPS therapy survived longer compared with patients given SMANCS-Lipiodol via the hepatic artery. The platinum concentrations in the tumor tissues were 23.3 times higher in seven operated cases and seven autopsy cases than those in the nontumorous tissues. This result suggests that LPS selectively accumu-lates in the tumor tissue, is long-lasting and gradu-ally releases the drug. LPS therapy is safe and effective as a new anti-cancer therapy for he-patocellular carcinoma.

View full abstract

Cellular immune parameters in peripheral blood were monitored for 4 weeks after chemoemboliza-tion with microencapsulated anticancer drugs, in order to investigate possible immune consequences after the therapy. The number and median age of the subjects were 30 and 63 (48-79), respectively. The subjects all had urological malignancies including 7 renal cell car-cinomas, 3 renal pelvic carcinomas, 13 bladder carcinomas and 7 prostatic carcinomas. Natural killer (NK) cell activity and CD4/8 ratio were augmented in 60% and 77% of the cases after chemoembolization respectively. Mature NK cell population (Leu7-CD16⁺) in these cases also showed a trend of contineous increase for more than 4 weeks. On the other hand, a small number of the patients showed an augmentation of CD3+ cells, I a-1⁺ cells or response to phytohemmagulutinin. These findings suggest that enhanced natural killer cell activity could be anticipated in more than a half of cases after chemoembolization.

View full abstract

Two kinds of basic amino acid(L-Arginine(Arg) and p-guanidino-L-phenylalanine(GPA))deriva-tives of aspirin and ibuprofen were synthesized and the hydrolyses of these compounds by trypsin(Tp) and carboxypeptidase B(CPase B)were investigat-ed to evaluate the availability as prodrugs for aspirin and ibuprofen. The ester bonds of these compounds were hydrolyzed by Tp at from about one-tenth to half the rate of N-α-benzoyl-Arg ethyl ester, a specific substrate for Tp, suggesting that the compounds are good substrates for Tp. Salicylic acid was generated in the hydrolysis of aspirin-Arg by CPase B after the hydrolysis of aspirin-Arg to salicyl-Arg, while ibuprofen was released by CPase B from ibuprofen-Arg. On the other hand, aspirin-and ibuprofen-GPA were not hydrolyzed by CPase B at all. These results suggest that drug-Arg ethyl esters are useful in the design of the prodrugs for non-steroidal anti-inflamma-tory carboxylic acids.

View full abstract