Effects of multimodal treatment and hyperthermia on hepatic tumors

The therapeutic results of Lp-TAE (transcatheter arterial embolization in the presence or absence of Gelfoam particles preceded by the infusion of a mixture of lipiodol and an anticancer drug via the proper hepatic artery) or DSM-TAE (transcatheter arterial embolization with degradable starch microspheres and the arterial injection of anticancer drugs via the hepatic artery) combined with hyperthermia were evaluated in 30 patients with hepatocellular carcinoma (HCC), 5 subjects with hepatic cholangiocarcinoma, and 22 patients with metastatic liver carcinoma. Hyperthermia was performed using an 8-MHz Thermotron RF-8. Tumor temperatures could be measured in 31 patients (54.4%) with malignant lesions of the liver who had undergone hyperthermia. The mean maximal temperature (T_max) was 41.5°C in the metastatic liver cancers. The efficiency of heating in HCC was unfavorable, i.e., the mean T_max was only 40.7 °C. The rise in tumor temperature was greater in either HCC or metastatic liver carcinoma associated with portal invasion of the lesion. The tumor-temperature elevation was also excellent in HCC that had been subjected to embolization with DSM in combination with hyperthermia. The response rate (complete response plus partial response) was as high as 40% (4/10) in the group in which the tumor temperature could be raised to 42°C or more. Among the 52 patients who had shown a high pretreatment level of tumor marker, that value decreased in 34 cases (65.4%), and the decrease was greater than 50% in 22 cases (42.3%).Presented at the Second International Symposium on Treatment of Liver Cancer. Taipei, 3–4 February 1991     

Effects of four antioxidants on N-methyl-N'-nitro-N-nitrosoguanidine initiated gastric tumor development in rats

The effects of antioxidant administration during the post initiation phase of gastric tumor development were investigated in male Wistar rats treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Animals (20/group) were given MNNG in the drinking water (100 mg/l) for 8 weeks, and for the duration of this treatment were also fed on diet supplemented with 10% sodium chloride. Thereafter, they were divided into 6 groups and were maintained on diet containing either 2% butylated hydroxyanisole (BHA), 1% BHA, 1% butylated hydroxytoluene (BHT), 1% ethoxyquin (EQ) or 1% DL-alpha-tocopherol (alpha-TP) for 32 weeks. A carcinogen control group was fed the basal diet without antioxidant supplementation. The experiment was terminated 40 weeks after the beginning of administration of MNNG and development of gastroduodenal tumors was determined histopathologically. EQ significantly increased the incidence of tumors in the glandular stomach. No modification of tumor development in this region of the organ were observed with 2% BHA, 1% BHA, 1% BHT or 1% alpha-TP, although both 2% BHA and 1% BHA induced and/or promoted tumor development in the forestomach. In addition, nephrocalcinosis was identified only in the kidneys of rats given EQ after MNNG treatment.     

Induction of hepatic tumors by diethylstilbestrol in N-nitrosobutylurea-initiated female rats

The carcinogenic effect of estrogens, diethylstilbestrol (DES) and 17 beta-estradiol (E2), and its modification by N-nitrosobutylurea (NBU) were studied in female W/Fu rats. Multiple mammary tumors (MT) of medullary carcinoma type developed at a high rate following prolonged treatment with estrogens. All MTs were located adjacent to the nipple and were slow-growing. The induction rate, multiplicity and size of estrogen-induced MTs were not influenced by pretreatment with a small amount of NBU, which alone did not induce any tumor. Ten of 12 rats (82%) receiving combined treatment with NBU and DES developed hepatic tumors (HT), while no rats in other treatment groups developed HT. All HTs were multiple nodules of various sizes bulging from the liver surface, and were considered to be neoplastic nodules. A high frequency of HT development was unexpected, because independent treatment with NBU or DES alone did not induce HT in female rats. It appears that DES played a role as a carcinogen, inducing MT and pituitary tumor (PT) through its estrogenic potency (like natural estrogen, E2), while it also acted as a promoter or co-carcinogen in the induction of HT through its pharmacologic effects. These findings may be relevant to an increased frequency of liver neoplasm among women taking oral contraceptives containing synthetic estrogens.     

Influence of hepatic tumors caused by diethylnitrosamine on hexachlorobenzene-induced porphyria in rats.

The response of female BDVI rats bearing diethylnitrosamine(DENA)-induced hepatic tumors to the porphyrinogenic action of hexachlorobenzene (HCB) was studied. (1) The heme pathway operates in these tumors but they were less affected by HCB than the liver. (2) Tumors did not accumulate porphyrins although the surrounding liver accumulated more porphyrins than livers treated with HCB. (3) DENA/HCB livers which developed a well defined tumor showed slightly less porphyrinogen carboxylyase inhibition and delta-aminolaevulinate synthase induction than HCB rats. (4) The results of the present work suggest that endogenously formed porphyrins would be unable to be accumulated by DENA-induced tumors when the tumoral development precedes the onset of the porphyria.     

Sex comparison of heme pathway in rats bearing hepatic tumors.

The present study was undertaken to explore the effect of the presence of hepatic tumors induced by diethylinitrosamine (DENA) on the metabolic heme pathway, and to assess whether these tumors can modify the response of rats to the porphyrinogenic drug hexachlorobenzene (HCB) and whether the above mentioned effects occur to a greater extent in females than males. The results obtained showed that: a) Females were more susceptible to the hepatocarcinogenicity of DENA than males. b) Female normal and DENA treated rats were more susceptible than male rats to the porphyrinogenicity of HCB. c) The presence of hepatic DENA induced tumors could diminish basal hepatic ferrochelatase activity. d) Hepatic tumors could modify the response of animals to a porphyrinogenic drug such as HCB. Thus, both female and male DENA/HBC rats accumulated more porphyrins and showed a lower delta-aminolevulinate synthase and uroporphyrinogen I synthase induction than HCB rats. e) The heme pathway was functional in DENA induced tumors in both male and female rats but they were little affected by HCB.     

Induction of hepatic tumors in rats by senkirkine and symphytine.

The carcinogenicity of the pyrrolizidine alkaloids senkirkine and symphytine was studied in male inbred ACI rats. Animals were divided into 3 groups: Group I received ip injections of freshly prepared senkirkine at a dose of 10% of the median lethal dose (LD50) twice weekly for 4 weeks and then once a week for 52 weeks. Group II received ip injections of symphytine at a dose of 10% of the LD50 by the same injection schedule as in group I. The control group was given ip injections of a 0.9% NaCl solution following the same injection schedule as in experimental groups. All group I rats survived for more than 290 days after the start of injections, and 9 of 20 rats developed liver cell adenoma. All group II animals survived for more than 330 days after the start of injections. Of 20 rats, 4 had liver tumors, 3 had hemangioendothelial sarcomas, and 1 had liver cell adenoma. The hemangioendothelial sarcomas showed metastasis in the lungs of 2 rats. The control group had no liver tumors.     

南方壁虎制剂对DEN诱导大鼠肝癌癌前病变的探讨

目的:探讨南方壁虎制剂对二乙基亚硝胺(DEN)诱导大鼠肝癌癌前病变的作用.方法:利用Solt-Farber的DEN诱导肝癌癌前病变短期动物模型,在制模过程中给予不同剂量的南方壁虎制剂进行干预,通过组织化学染色观察各组动物肝组织内r-谷氨酰转肽酶阳性肝细胞增生灶(r-GT灶)的数量和面积,以及免疫组化SP法对肝组织中的Ki-67、EFGR和ErbB4蛋白表达进行检测分析.结果:不同剂量南方壁虎实验组γ-GT阳性灶的数量、面积均小于DEN对照组,其中低剂量组显示差异有统计学意义,P<0.05.各组肝组织均表达Ki-67、EGFR和ErbB4.Ki-67在低剂量组中的阳性和强阳性的表达率(20.0%)与阳性对照组(73.3%)差异有统计学意义,P<0.05;EGFR在高剂量和低剂量的阳性和强阳性的表达率分别为22.2%和10.0%,与阳性对照组(40.0%)差异有统计学意义,P<0.05;ErbB4不同剂量组的表达均高于阳性对照组,差异无统计学意义,P>0.05.结论:南方壁虎制荆对DEN诱发大鼠肝癌癌前病变有一定的抑制作用;Ki-67、EGFR可能参与南方壁虎抑制肝癌癌前病变的调节作用.     

Effects of phenolic antioxidants in low dose combination on forestomach carcinogenesis in rats pretreated with N-methyl-N'-nitro-N-nitrosoguanidine

The combined effects of low doses of promoters or carcinogens on two-stage forestomach carcinogenesis were examined in rats pretreated with N-methyl-N'-nitro-N-nitrosoguanidine. Groups of 15 rats were given a single 150 mg/kg body weight intragastric dose of N-methyl-N'-nitro-N-nitrosoguanidine. Starting 1 week later they were fed a diet containing low doses of known forestomach promoters/carcinogens (0.5% caffeic acid, 0.2% catechol, 0.5% butylated hydroxyanisole, or 0.25% 2-tert-butyl-4-methylphenol), alone or in combination, or basal diet without antioxidant supplement for 35 weeks. Histopathological examination revealed the incidences of forestomach squamous cell carcinomas in animals treated with N-methyl-N'-nitro-N-nitrosoguanidine followed by caffeic acid, catechol, butylated hydroxyanisole, 2-tert-butyl-4-methylphenol, and basal diet to be 27, 20, 13, 13, and 7%, respectively, whereas the incidence increased to 80% by the combined treatment with these four chemicals. The present results thus show that although the low doses of individual promoters/carcinogens did not have significant promoting activity, their combination exerted a strong enhancing influence on rat forestomach carcinogenesis. The findings indicate the importance of summation and synergism at a low dose for agents present in the human environment.     

Malignant tumors in rats fed nafenopin, a hepatic peroxisome proliferator.

Nafenopin (2-methyl-2-[P-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy] propionic acid; Su-13,437), a potent hypolipidemic hepatic peroxisome proliferator, was fed to male F344 rats at a dietary concentration of o.1% until the end of the experiment at 25 months. Between 18 and 25 months, 12 of 15 rats (80%) developed tumors. Approximately 73% (11/15) developed hepatocellular carcinomas, and 10% (3/15) developed pancreatic acinar cell tumors, including 1 metastasizing carcinoma. The hepatocellular carcinomas as well as the acinar cell carcinoma of the pancreas were transplantable successfully through 6 generations.     

Effects of forced diuresis on butylbutanolnitrosamine induction of bladder tumors in rats

The study was concerned with the effect of forced diuresis on the frequency and morphologic pattern of bladder cancer induced with butylbutanolnitrosamine in rats. An 1.6 times increase in diuresis was followed by inhibition of bladder carcinogenesis, resulting in a 2.5-fold decrease in the tumor rate as compared to controls. The data obtained confirm the earlier suggested hypothesis of "urothelial contact" as well as epidemiologic data.     

Effects of antioxidants on fiber mutagenesis

Recent studies from this laboratory have shown that asbestosfibers are mutagenic in cultured mammalian cells when assayedusing a system that can detect multilocus deletions. Southernanalysis of the induced mutants shows that the majority containlarge deletions ranging in size from a few thousand to severalmillion basepairs. In the present study, the effects of freeradical scavenging enzymes on the cytotoxic and mutagenic potentialof chrysotile fibers were examined using the human-hamster hybrid(A_L) cells. Exponentially growing cells were treated with gradeddoses of fibers for a 24 h period either in the presence orabsence of catalase, superoxide dismutase (SOD) or Tempol. Fiber-exposedcells were treated with the various enzymes either concurrentlywith the fiber or extended through the entire expression period.While the survival of A_L cells treated with graded doses ofchrysotile fibers with or without a concurrent treatment withSOD and catalase was not significantly different, the mutationyield at the SI locus was significantly reduced in cells treatedwith these antioxidant enzymes. Furthermore, cells treated withthe enzymes for a prolonged period were not better protectedthan those treated only during fiber treatment. The SOD mimicnitroxide, Tempol, had no effect on either the survival or mutagenicyield of chrysotile fibers. While SOD and catalase reduced themutagenic potency of asbestos fibers in AL cells, they did notalter the molecular spectrum of fiber-induced mutagenesis. Ourresults indicate that antioxidant enzymes can protect cellsagainst the genotoxic damages induced by chrysotile fibers,and are highly suggestive of the roles of oxyradicals in thefibrogenic and carcinogenic mechanisms of asbestos fibers.     

Potent inhibition of aflatoxin-induced hepatic tumorigenesis by the monofunctional enzyme inducer 1,2-dithiole-3-thione.

1,2-Dithiole-3-thiones are five-membered cyclic sulfur-containing compounds with antioxidant, chemotherapeutic, radioprotective and chemoprotective properties. Several substituted 1,2-dithiole-3-thiones are used medicinally and one of these, oltipraz [5-(2-pyrazinyl)-4-methyl-1,2-dithiole-3-thione], has been recently shown to be an inhibitor of aflatoxin B1 (AFB1) hepatocarcinogenesis in the rat. Structure-activity studies have been undertaken to probe the mechanisms by which dithiolethiones inhibit carcinogenesis. Such studies revealed that unsubstituted 1,2-dithiole-3-thione was more effective than oltipraz at inhibiting aflatoxin-DNA adduct formation in vivo and at inducing electrophile detoxication enzymes in cell culture. In the present studies the effects of dietary administration of 1,2-dithiole-3-thione on the induction of xenobiotic metabolizing enzymes and inhibition of aflatoxin-induced hepatic tumorigenesis were examined. Male F344 rats were fed graded doses of 1,2-dithiole-3-thione (0.001-0.03%) for 4 weeks. During the second and third weeks of 1,2-dithiole-3-thione feeding, rats were dosed by gavage with 250 micrograms of AFB1/kg five times a week. Rats were then restored to control AIN-76A diet 1 week after cessation of AFB1 dosing. At 4 months, focal areas of hepatocellular alteration were identified and quantified by staining sections of liver for gamma-glutamyltranspeptidase (GGT) activity and glutathione S-transferase P (GST-P) expression. Treatment with 1,2-dithiole-3-thione at the lowest dose (0.001%) reduced by greater than 80% the volume of liver occupied by GGT or GST-P foci; higher dietary concentrations provided greater than 98% reductions in the volume per cent of these markers for presumptive preneoplastic lesions. All dietary concentrations of 1,2-dithiole-3-thione resulted in significant elevations in hepatic GST activities. In accord with the protective effects against tumorigenesis, 4- to 6-fold increases in the specific activities of aflatoxin-glutathione conjugation were observed in cytosols prepared from livers of animals fed 1,2-dithiole-3-thione. By contrast, 1,2-dithiole-3-thione did not have any detectable inductive effects on hepatic microsomal cytochrome P450 levels or activities. Dietary administration of 1,2-dithiole-3-thione also elevated activities of GSTs and other phase II enzymes in several extrahepatic organs. This broad pattern of induction of detoxication enzymes by 1,2-dithiole-3-thione supports the potential widespread use of this compound as a protective agent against chemical carcinogenesis and other forms of electrophile toxicity.     

Comparative developmental and phenotypic properties of altered hepatocyte foci and hepatic tumors in rats

Previous investigations in this laboratory have provided evidence that histochemically detectable altered hepatocyte foci and hepatic tumors appearing in rats given a single neonatal treatment with a low dose of carcinogen followed by chronic dietary phenobarbital administration are developmentally independent. The present investigation further evaluates developmental relationships among these lesions. Altered hepatocyte foci were divided into two subclasses consisting of foci that were detectable by histochemical as well as by hematoxylin-eosin staining [designated hist(+)/morph(+) foci] and those foci that were detectable solely by histochemical staining [designated hist(+)/morph(-) foci]. The developmental and phenotypic properties of the hist(+)/morph(-) foci, hist(+)/morph(+) foci, and hepatic tumors were compared in rats initiated once neonatally with different doses of diethylnitrosamine and promoted with dietary phenobarbital from weaning. The morph(+) and morph(-) lesion subclasses were distinguishable on the basis of several developmental characteristics. Hist(+)/morph(+) foci were present at low frequency until at least 150 days after initiation. Although the development of hist(+)/morph(-) foci was essentially complete at that point, the rate of appearance of hist(+)/morph(+) increased significantly. The diethylnitrosamine dose response of the hist(+)/morph(+) foci followed the histochemical marker patterns of the tumor lesion class more closely than that of the hist(+)/morph(-) group. The rates of expression of the hist(+)/morph(+) foci increased with the increasing level of histochemical complexity, whereas the rates of expression of the hist(+)/morph(-) foci groups were inversely correlated to their complexity level. Although the average focus size or diameter in the hist(+)/morph(+) groups was greater than that of the hist(+)/morph(-) foci, the focus growth rates of morph(+) and morph(-) subsets matched for histochemical phenotype were comparable. The complexity level and individual marker distribution patterns of the hist(+)/morph(+) focus class were more similar to tumor patterns than to the distribution patterns of the hist(+)/morph(-) lesion class. The results suggest the following. (a) The development of lesion classes with successively greater deviation from normalcy does not occur via lineal progression from less to more deviated forms within a given lesion class. The three lesion classes appear to develop independently, with the developmental characteristics of each lesion class determined at the time of initiation.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of separate and combined treatments with gamma radiation and diethylnitrosamine in neonatal rats on the induction of altered hepatocyte foci and hepatic tumors

To characterize the effects of combined treatments with gammaradiation and diethylnitrosamine (DEN) on the induction of histochemicallydetectable altered hepatocyte foci and hepatic tumors, we assessedthe yields of these lesions in the livers of 150-day-old ratsthat had been treated neonatally with a single dose of gammaradiation (75 red, whole body) and i.p.-injected DEN (0.15 µmol/gbody wt), either separately or in combination. The combinedtreatments involved the administration of the two stimuli inboth possible sequences, with the interval between treatmentsset at 1 h. The focus population was examined for two histochemicalmarkers (elevated gamma-glutamyl transpeptidase [GGT(+)J andiron exclusion [FE(–)], giving rise to three detectablefocus phenotypes, i.e. GGT(+) foci, FE(–) foci, and GGT(+),FE(–) foci. Frequencies of the three phenotypes were quantitatedthrough the use of serial frozen sectioning techniques and computer-assistedimage analysis. GGT(+) focus induction was synergistkally enhancedby the combined treatment irrespective of the order in whichthe two stimuli were administered; the remaining two phenotypesdid not show such enhancement. The magnitude of the GGT(+) focusresponse was significantly greater when the treatment sequencewas gamma DEN as opposed to DEN gamma. Tumor yields in ratsreceiving combined gamma-DEN treatment were similar to thosein rats receiving the DEN alone, irrespective of the gamma-DENtreatment sequence. These results suggest that (i) phenotypicallydistinguishable lesions, including foci with different histochemicalmarker patterns and tumors, originate from specific types ofdamage at different genetic loci and are developmentally independent;and (ii) the expression of the GGT(+) marker per se in alteredhepatocyte foci is not a reliable index of incipient hepaticneoplasia.     

Radioembolization of hepatic tumors

Unresectable primary and metastatic liver tumors are a leading cause of cancer mortality and morbidity. This remains a challenging and key task for every oncologist despite significant advances that have been made with selective targeted systemic agents and in technology advances with radiotherapy delivery. Radioembolization (RE) is a technique of permanently implanting microspheres containing Yttrium-90 (⁹⁰Y), a beta-emitting isotope with a treatment range of 2 mm, into hepatic tumors. This form of brachytherapy utilizes the unique dual vascular anatomy of the liver to preferentially deliver radioactive particles via the hepatic artery to tumor, sparing normal liver parenchyma. The main treatment inclusion criteria are patients with solid tumors, compensated liver functions, life expectancy of at least three months, and ECOG performance status 0-2. Benefit of RE has been proven in patients that have low-to-moderate extrahepatic disease burden, prior liver radiotherapy, heavy prior chemotherapy and biologic agent exposure, and history of hepatic surgery or ablation. Most of the clinical evidence is reported in metastatic colorectal, and neuroendocrine tumors (NET), and primary hepatocellular cancer. A growing body of data supports the use of RE in hepatic metastatic breast cancer, intrahepatic cholangiocarinoma, and many other metastatic tumor types. Side effects are typically mild constitutional and GI issues limited to the first 7-14 days post treatment, with only 6% grade 3 toxicity reported in large series. Potentially serious or fatal radiation induced liver disease is extremely rare, reported in only 1% or fewer in major series of both metastatic and primary tumors treated with RE. Currently, high priority prospective clinical trials are testing RE combined with chemotherapy in first line therapy for colorectal hepatic metastases, and combined with sorafenib for hepatocellular carcinomas (HCCs). Fortunately, this beneficial and now widely available therapy is being increasingly incorporated into the standard therapy algorithms of multidisciplinary GI cancer teams worldwide. This form of radiotherapy differs significantly from daily external beam radiotherapy in many ways, particularly in dose rate, dosimetric coverage and duration of radiation delivery, side effects, and patient selection factors. A wealth of experience using RE in solid tumors exists and ongoing major prospective clinical trials will soon clarify the role of RE in the management of metastatic colorectal liver metastases.     

Palliation of hepatic tumors

Palliation is treatment aimed at alleviating the symptomatic effects of a disease rather than at curing the disease. The four most common types of liver tumors that often require palliative treatment include hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), metastatic colorectal carcinoma (mCRC), and metastatic neuroendocrine tumors (mNET). Modalities employed in the palliative treatment of these tumors most often include resection, stenting, chemotherapy, radiation, ablation, and the general treatment of liver failure symptoms. Many of these modalities can be applied to the palliative care of all hepatic tumor types, regardless of the specific tumor histology--as incurable cancers often converge along a final common pathway. We herein provide a review of the therapeutic approaches to palliate hepatic tumors, as well as how such therapies are designed to alleviate the symptoms of patients with end-stage liver tumors.