172 Cancer and Oxidative Slress

18.21 CYSTEAMINE AND ITS PHENOLIC ANALOGUES INHIBIT THE PROLIFERATION OF NORMAL, LEUKEMIC AND DRUG RESISTANT LEUKEMIC T CELLS. Thomas M. Jeitner and Nicholas H. Hunt, Department of Pathology, The University of Sydney, New South Wales 2006, Australia.

Cysteamine inhibits the growth of prolactin-secreting pi tu i tary tumours (Jeitner and Oliver, 1990, J. Endocrinol., in press). Recently, we have shown that iron chelators and antioxidants inhibit the proliferation of murine T-cells (Chaudhri et al., 1988, Cell. lmmunol. 115, 204). Since cysteamine is an antioxidant which is current ly used for the t reatment of nephropathic cystinosis we investigated the ability of this compound and its phenolic analogues, 2- and 4-aminothiophenol, to inhibit the proliferation of normal, leukemic and drug resistant leukemic T ceils, Human peripheral blood lymphocytes were prepared from "buffy coats" and stimulated with phorbol myristate acetate and ionomycin and treated with the drugs 24 hours following stimulation, for a further 24 hours. CCRF-CEM cells and variants thereof resistant to methotrexate and vinblastine were also exposed to the drugs for 24 hours. Proliferation was assessed by [3H]-thymidine uptake and enumerat ion. Viabil i ty was ascertained by eosin exclusion. Cysteamine caused a dose dependent inhibition of proliferation in the millimolar range in all of the cell types examined. Similarly, 2- and 4-aminothiophenol inhibited cellular proliferation, but in the micromolar range. Therefore, the antioxidant compound cysteamine and its analogues are potential oncostat ic drugs, particularly in cases of drug resistance.

CONPARATIVE STUDY ON PLASNA LIPID PEROXIDE LEVELS

ANONG OVARI~ CANCER PATIENTS AND NORNAL CONTROLS

Lan Kai-Wei et at

Department of Biochemistry, Sichuan Cancer I n s t i t u t e ,

Chengdu, P. R. China

I t has been ctalmed tha t l ip id peroxide (LPO) might

be a s soc i a t ed with ca rc inogenes i s process . The th io -

b a r b i t a r i c acid ~TBA) method has been widely used in

c i i n i c a t f i e l d s .

The purpose of th i s s tudy is to eva tu te i t s u s e l u l -

hess and l i m i t a t i o n s in d i agnos i s of ovar ian cancer.

46 hea l thy women, Without evidence of malignant or the

other d i sease , between 25 and 50 years of aoe served

as normal cont ro l s , LPU mean values measured were

8.56±0. B2 naol 'ml (M±SD) ~5 proved with ovar ian

cancer cases, LPU mean values were 4 .92± 0.99 naoi .mt ;

11 gynecological tumours eases. LPU mean va lues were

2 .61±1 .37 nmol mi; 2 ovary cys t s cases, LPO mean va lues

were 2 .75±0 .68 nmot.ml. These r e s u l t s showed that LP0

leve ls in ovarian cancer pat ients were s i g n i f i c a n t l y

e levated.

18.22

18.23 RELIEVING CANCER PATIENTS FROM OXIDATIVE STRESS BY A PROTEIN BOUND POLYSACCHARIDE (KRESTIN). Kazutoshi Kariya, Kunie Nakamura, Keiko Nomoto*, Sumio Matama#, and Katsunori Saigenji# Mol Biol Lab, Dept Biochem*, ~ and Dept Internal Med., Kitasato University School of Med., 1-15-I Kitasato, Sagamihara, Kanagawa, 228 Japan.

KRESTIN (a protein bound polysaccharide of Basi- diomycetes) has long been used in cancer chemo- therapy as one of the harmless BRMs, without elucidation of the mode of action. We found that Krestin mimicks the SOD act iv i ty by in vitro analysis. We intended to confirm this SOD mimetic act iv i ty in cancer bearing hosts. Procedures: ( I) SOD mimetic act iv i ty of Krestin was quantitated by NBT, CLA, ESR, HgOg-production, comparing with authentic bovine RBC-~OD. (2) Wister rat trans- planted with Walker 256 fibrosarcoma were moni- tored on their RBC-O~ by the newly devised method (K. Nakamura). (3): Randomly selected patients with digestive tract neoplasmas were perorally prescribed by Krestin 3g/day for 7 days, and traced for other 7 days on their O~ levels in plasma and RBC. Results: (q) Tumor bearing rats showed increase in RBC-O~ with tumor growth. By 4 hours after a single ip injection of Krestin 50 mg/kg, RBC-O~ decreased, and then returned to a high level. (3) Cancer patients (50) showed 2.5 times higher RBC-O~. Krestin drastically dec- reased plasma-O~ at ~irst , and then followed by RBC-O~. Plasma~O~ increased even during the drug use. c RBC-O~ re~ained at a low level, and in- creased afteP cessation of the drug. Conc]usion: Krestin with SOD mimicking act iv i ty is applicable to relieve oxidative stress in cancer patients.

CORRELATION OF DNA BASE OXIDATION WITH THE ACTIVATION OF K-ras ONCOGENE IN NICKEL-INDUCED RENAL TUMORS Kazimierz S. Kasprzak, Kathleen Higinbotham, Bhalchandra A. Diwan, Alan O. Perantoni, and Jerry M. Rice Laboratory of Comparative Carcinogenesis, National Cancer Insti tute and Biological Carcinogenesis and Development Program, PRI, FCRDC, Frederick, MD 21701, U.S.A.

Renal mesenchymal tumors were induced in male F344/NCr rats by local injection of nickel subsulfide powder (Ni~Sz) alone or admixed with metallic iron powder (Fe °) or magnesium basic carbonate (MgCarb). Fe ° enhanced while MgCarb inhibited Ni3S 2 carcinogenesis (Kasprzak et at., Proc. Am. Assoc. Cancer Res., 31: 127, 1990). DNA isolated from 11 of 16 such tumors contained K-ras oncogene activated by a specific point mutation, GGT ~ GTT transversion in codon 12. Nickel carcinogens are known to activate dioxygen and enhance oxidation of the DNA guanosine to i ts 8-hydroxy deri,vative (8-OHdG) both in vitro (Kasprzak and Hernandez, Cancer Res., 49: 5964, 1989) and in vivo (Kasprzak et at., Carcinogene- sis, 11: 647, 1990), On the other hand, the presence of 8-OHdG in oligodeoxynucleotide templates causes nucleotide misincorporation opposite the lesion that results in G ~ T trans- version (Shibutani et at., Proc. Am. Assoc. Cancer Res., 31: 93, lggo). Thus, the results of our experiments support the hypothesis that nickel carcinogenesis is mediated through oxidative DNA damage.

18.24