Showing papers on "Cancer cell published in 1986"

Phenol red in tissue culture media is a weak estrogen: implications concerning the study of estrogen-responsive cells in culture

Abstract: Although much attention has been paid to the removal of hormones from sera and to the development of serum-free media for studies on hormone-responsive cells in culture, little consideration has been given to the possibility that the media components themselves may have hormonal activity. We have found that phenol red, which bears a structural resemblance to some nonsteroidal estrogens and which is used ubiquitously as a pH indicator in tissue culture media, has significant estrogenic activity at the concentrations (15-45 microM) at which it is found in tissue culture media. Phenol red binds to the estrogen receptor of MCF-7 human breast cancer cells with an affinity 0.001% that of estradiol (Kd = 2 X 10(-5) M). It stimulates the proliferation of estrogen receptor-positive MCF-7 breast cancer cells in a dose-dependent manner but has no effect on the growth of estrogen receptor-negative MDA-MB-231 breast cancer cells. At the concentrations present in tissue culture media, phenol red causes partial estrogenic stimulation, increasing cell number to 200% and progesterone receptor content to 300% of that found for cells grown in phenol red-free media, thereby reducing the degree to which exogenous estrogen is able to stimulate responses. The antiestrogens tamoxifen and hydroxytamoxifen inhibit cell proliferation below the control level only when cells are grown in the presence of phenol red; in the absence of phenol red, the antiestrogens do not suppress growth. The estrogenic activity of phenol red should be considered in any studies that utilize estrogen-responsive cells in culture.

Growth and metastasis of tumor cells isolated from a human renal cell carcinoma implanted into different organs of nude mice.

Abstract: The purpose of this study was to determine whether the methods for isolating tumor cells from a human renal cell carcinoma (HRCC) influence the biological behavior of the cancer cells. Renal cell carcinoma obtained from a surgical specimen was dissociated by enzymatic treatment and cells were plated into culture dishes or injected s.c. into the kidney of BALB/c nude mice. The resultant kidney tumor produced liver metastasis and ascites. All tumors growing in nude mice (s.c., kidney, liver, ascites) were also established in culture. The human origin of all five lines was ascertained by karyotypic and isoenzyme analyses. Cells from all lines were injected, s.c., i.p., i.v., intrasplenically, and beneath the renal capsule of nude mice. All the lines were tumorigenic after s.c. or renal subcapsule injection, although the rate of tumor growth varied among the five lines. The metastatic behavior of the HRCC cells was influenced by both the nature of the tumor cells and the route of injection into nude mice. In general, cells derived from the liver metastasis produced more metastases in nude mice than other lines. The lines established in culture from the primary HRCC and the ascites were poorly metastatic. Even with highly metastatic cells, i.v. injection did not yield significant metastasis, but the injection of cells into the renal subcapsule resulted in extensive metastasis to the lungs and in all peritoneal organs. These results indicate that nude mice can be used for the isolation of populations of HRCC cells with different growth and metastatic potential and that, of the organ sites tested, the renal subcapsule is the most advantageous site for implantation of HRCC cells.

Tumor necrosis factor: a potent effector molecule for tumor cell killing by activated macrophages.

Abstract: Activated macrophages (aM phi) destroy more effectively cancer cells than normal cells. The mechanism by which macrophages destroy cancer cells is not known. We report here that tumor cells susceptible to aM phi were killed by recombinant (r) tumor necrosis factor type alpha (TNF-alpha), whereas variant tumor cells resistant to aM phi after selection in vitro or in vivo were resistant to killing by rTNF-alpha. The converse selection for rTNF-alpha-resistant variants resulted in cells that were also resistant to killing by aM phi. The sensitivity of macrophage-resistant variants was not changed to other tumoricidal cells or soluble mediators, except that the macrophage-resistant variants were also resistant to the effects of another cytotoxic protein, B-cell lymphotoxin, which is structurally related to rTNF-alpha. Similar results were obtained regardless of whether short-term or long-term cytotoxic effects of aM phi were measured. Finally, it was shown that killing of tumor cells by murine aM phi was completely inhibited with a polyclonal antibody that neutralizes the effects of murine TNF-alpha. These results suggest a major role for TNF-alpha in tumor cell destruction by aM phi in vitro and in vivo.

Oncogene amplification in tumor cells

Abstract: Publisher Summary This chapter summarizes the third mechanism of oncogene activation—oncogene amplification. It illustrates the various ways by which the oncogenic potential of different proto-oncogenes can be activated. Because of the involvement of myc oncogenes in amplifications in a variety of tumors, other lesions that also activate the cellular oncogene c-myc and the aspects of the normal regulation of this oncogene are also described. Since its discovery in drug-resistant eukaryotic cells, somatic amplification of specific genes has been implicated in an increasing variety of adaptive responses of cells to environmental stresses. Experimental work on drug-resistant cells has shown that in the absence of a selection pressure (drug), double minute chromosomes (DMINs) and the amplified genes that they contain are lost, whereas amplified DNA in the form of homogeneously staining regions (HSRs) is retained in the cells. If DMINs and HSRs contain amplified genes that encode drug-resistant or growth-stimulating protein products, it would follow that the more stable chromosomal form, the HSR, confers a greater selective growth advantage for cells. Although DMINs and HSRs have been described predominantly in tumor cells selected for the resistance to cytotoxic drugs, it is also clear that DMINs and HSRs may be present in cancer cells before the start of therapy.

Secretion of an insulin-like growth factor-I-related protein by human breast cancer cells

Abstract: Somatomedin activity is required for proliferation of normal cells; recently somatomedin activity in the cellular environment was shown to be necessary for expression of the transformed phenotype. We demonstrate here that authentic serum-derived insulin-like growth factor-I (IGF-I) stimulates the proliferation of four human breast cancer cell lines, MCF-7, MDA-MB-231, ZR-75-1, and Hs578T in serum-free monolayer culture and that each of these lines produces and secretes an IGF-I-related growth factor. The two highly tumorigenic estrogen-independent cell lines, MDA-MB-231 and Hs578T, produced 2- to 10-fold more IGF-I than did two estrogen responsive cell lines, MCF-7 and ZR-75-1, which are not tumorigenic in the absence of estrogen. These breast cancer cells also secrete a Mr 50,000 binding activity which partially obscured detection of IGF-I by radioimmunoassay. Acid-ethanol extraction allowed dissociation of the high molecular weight complex; whereupon, fully immunoreactive IGF-I comigrated on acid gel exclusion chromatography with authentic human serum-derived IGF-I. Radioimmunoassay displacement curves for breast cancer cell line-derived IGF-I were parallel to those for authentic IGF-I. Northern blot analysis of mRNA from four breast cancer cell lines demonstrated specific hybridization with a human IGF-I probe corresponding to one of the two major transcripts seen in human liver mRNA. These data suggest that breast cancer cell line-derived IGF-I is similar to liver-synthesized, serum-derived IGF-I.

Differential killing of human carcinoma cells supplemented with n-3 and n-6 polyunsaturated fatty acids.

Abstract: The effects of essential fatty acids on cell proliferation and cell viability of 3 human tumor and 4 normal cell lines were tested in vitro. It was found that n-3 and n-6 fatty acids supplemented at 20 micrograms/ml killed human breast, lung, and prostate cancer cells selectively. Normal human fibroblasts and other normal cells were not killed, but their rate of division was lowered. The most selective cytotoxic effects were obtained with fatty acids containing 3, 4, and 5 double bonds. The degree of inhibition of growth and/or loss of viability depended on a given fatty acid, on cell density, on fatty acid concentration, and on the type of cell. When eicosapentaenoate, gammalinolenate, or arachidonate was added to cocultures made of human cancer cells with normal fibroblasts, the cancer cells were selectively eliminated. These results, combined with the observation that certain fatty acids coupled to cytotoxic agents may enhance the cytotoxic activity, suggest that treatment of cancer with polyunsaturated fatty acids containing 3, 4, and 5 double bonds has potential clinical usefulness.

Induction of Epidermal Growth Factor-Related Polypeptides by 17β-Estradiol in MCF-7 Human Breast Cancer Cells

Abstract: MCF-7 human breast cancer cells release polypeptides related to insulin-like growth factor-I (IGF-I) and epidermal growth factor (EGF) into serum-free culture medium (CM). Treatment of MCF-7 cells with 17β-estradiol, which is required in vivo for MCF-7 tumor growth in the nude mouse and stimulates the MCF-7 growth rate in vitro, resulted in selectively enhanced growth factor activities in CM. Autostimulatory growth-promoting activity was elevated at least 2-fold, and EGFlike polypeptides were elevated 5-fold but IGF-I immunoreactivity was not elevated. Several species of estrogen-induced receptor- reactive EGF-like polypeptides, suggestive of high molecular weight transforming growth factorα, were detected after gel exclusion chromatography of CM extracted with 1 M acetic acid. A 30,000 mol wt peak of EGF receptor competing activity comigrated with a peak of autostimulatory and fibroblast-transforming activity. It is possible that estradiol stimulation of MCF- 7 growth and/or tumor formation may depend on...

Similar biochemical changes associated with multidrug resistance in human breast cancer cells and carcinogen-induced resistance to xenobiotics in rats

Abstract: MCF7 human breast cancer cells selected for resistance to doxorubicin (adriamycin; DoxR) have developed the phenotype of multidrug resistance. Multidrug resistance in DoxR MCF7 cells (called AdrR MCF7 cell line in previous publications) is associated with biochemical changes similar to those induced by carcinogens in rat hyperplastic liver nodules (HNs) and associated with resistance to xenobiotics in that system. In HNs and DoxR cells, exposure to a single agent results in the selection of cells that are cross-resistant to a wide variety of structurally dissimilar toxic agents. Resistance in both systems is associated with decreases in intracellular accumulation of toxins and changes in phase I (decreased cytochrome P1-450) and phase II (increased glutathione transferase and glucuronyltransferase) drug-metabolizing activities. In HNs and DoxR cells, resistance is associated with the induction of relatively stable levels of an immunologically related anionic glutathione transferase isozyme (EC 2.5.1.18). The finding of similar biochemical changes associated with the development of resistance to various xenobiotics in HNs and to many naturally occurring antineoplastic agents and at least one carcinogen (benzo[a]pyrene) in DoxR MCF7 cells suggests that the mechanisms of resistance in these two models may be similar.

Autocrine Growth Stimulation of the MCF 7 Breast Cancer Cells by the Estrogen-Regulated 52 K Protein

Abstract: The growth of MCF 7 human breast cancer cells is stimulated in vitro by estradiol (E2) and we have previously shown that estrogen-regulated glycoproteins released into the culture medium can partly mimick this effect. In this paper, we evaluate the mitogenic activity of the 52 K glycoprotein, which is a major E2-stimulated protein released by MCF 7 cells. The 52 K protein was purified 600-fold by affinity chromatography on Concahavalin A and an anti-52 K monoclonal antibody Sepharose columns. The 99% purified 52 K protein fraction stimulated the growth of estrogen-deprived MCF 7cells. A mean 1.7-fold increase was obtained with nanomolar concentrations of seven different preparations of 52 K protein. This stimulation represented 40% of the mitogenic effect of E2. Both the 52 K protein and E2 induced microvilli at the cell surface but the effect of the 52 K protein ocurred earlier. Other putative growth factors which are also stimulated by E2 and observed by [35SJcysteine labeling did not comigrate with the...

Autocrine and paracrine growth regulation of human breast cancer

Abstract: We consider the hypothesis that estrogen control of hormone dependent breast cancer is mediated by autocrine and paracrine growth factors secreted by the breast cancer cells themselves. Though we show direct, unmediated effects of estrogen on specific cell functions, we also provide evidence that human breast cancer cells secrete a collection of growth factors (IGF-I, TGFα, TGFβ, a PDGF-like competency factor, and at least one new epithelial colony stimulating factor). Some of these are estrogen-regulated in hormone dependent cells, and are constitutively increased in cells which acquire independence either spontaneously or byras transfection. Collectively, the secreted growth factors are capable of promoting tumor formation by MCF-7 cells in nude mice, though not to the same extent as estrogens. There would seem to be potential for clinical intervention in the autocrine and paracrine control of breast cancer cells, including some cells which are no longer dependent on estrogens.

Estrogen-induced factors of breast cancer cells partially replace estrogen to promote tumor growth

Abstract: The hormone 17 beta-estradiol acts through its receptor system to induce MCF-7 human breast cancer cells to form tumors in athymic mice. In vitro studies have identified the production of estrogen-induced growth factors from MCF-7 cells that may have a role in growth control. These induced growth factors were sufficient to stimulate MCF-7 tumor growth in ovariectomized athymic mice, thus partially replacing estradiol. Growth factors may act as estrogen-induced "second messengers" in estrogen-responsive growth of human breast cancer.

Serum-free growth of adult human prostatic epithelial cells.

Abstract: Proliferation of adult human prostatic epithelial cells in serum-free medium occurs upon the addition of cholera toxin, epidermal growth factor, pituitary extract, and hydrocortisone to basal medium PFMR-4A. Insulin and selenium enhance proliferation and permit growth at lower cell densities. Reducing the level of calcium in the medium dramatically alters morphology and also seems to increase proliferation. Mortal strains of cells derived from normal central or peripheral zone, benign hyperplasia, or cancer respond similarly to growth factors and calcium, but two populations of cancer cells which have been long-lived and may be immortal lines behave differently. GKC-CA cells require serum proteins or high levels of pituitary extract for optimal growth, and neither GKC-CA cells or cells of another cancer line, WB-CA, proliferate well in medium containing reduced levels of calcium. These observations may, however, be a reflection of attachment phenomena rather than of growth responses per se. Growth of cells in serum-free medium has allowed definitive studies of the effects of androgens, and regardless of cell type no response to androgens of prostate epithelial cells under any experimental conditions has been seen.

Effects of melatonin on cancer: studies on MCF-7 human breast cancer cells in culture.

Abstract: There is some evidence to suggest that the pineal gland influences neoplastic growth. Either crude or partially-purified pineal extracts have been used to treat malignant neoplasms in humans. More compelling evidence indicates that the pineal hormone melatonin, in addition to its well known antireproductive effects, may also exert oncostatic effects particularly in animal models of human breast cancer. However, it is not clear whether melatonin inhibits mammary cancer growth via an indirect neuroendocrine mechanism or via an action directly on the cancer cells themselves. Studies are described in which physiological concentrations of melatonin are shown to have marked inhibitory effects directly on MCF-7 human breast cancer cell growth in culture. Supra- or subphysiological levels of melatonin are completely ineffective in retarding breast cancer cell proliferation. Precursors and metabolites of melatonin such as serotonin, N-acetylserotonin and 6-hydroxymelatonin do not inhibit MCF-7 cell growth. Similarly, neither 5-methoxytryptophol nor 5-methoxytryptamine, regarded by some to be putative pineal hormones, exhibit antimitogenic properties. Melatonin completely blocks the estradiol-induced stimulation of MCF-7 cell proliferation. In defined, serum-free medium, melatonin loses its antimitogenic capabilities unless cells are also simultaneously exposed to either estradiol or prolactin. Therefore, the antiproliferative effect of melatonin may be dependent on the presence of serum and a complex interaction with hormones such as estradiol and/or prolactin.

Transforming gene in human atherosclerotic plaque DNA.

Abstract: The monoclonal hypothesis equates atherosclerotic plaques with benign smooth muscle cell tumors and proposes that plaques can arise via mutational or viral events. Here, we provide direct evidence that molecular events, heretofore associated only with tumor cells, are common to plaque cells as well. Three distinct groups of human coronary artery plaque (hCAP) DNA samples transfected into NIH 3T3 cells gave rise to transformed foci. DNA samples from a panel of normal noncancerous human tissues, including coronary artery, were negative in the assay. Southern-blotted focus DNA yielded positive signals when hybridized to the 32P-labeled nick-translated repetitive human "Alu" DNA sequence. The DNA from cloned foci was used successfully in a second round of transfection. Focus DNA hybridized to nick-translated v-Ki-ras, v-Ha-ras, or N-ras probes failed to detect human fragments of these genes. Primary focus cells from each of five clones elicited tumors after injection into nude mice (6/42). Several distinct high molecular weight (greater than 6.6 kilobases) bands were detected after BamHI-digested tumor DNA was hybridized to Alu. Preliminary characterization of these hCAP DNA-associated tumors indicates that they are similar to the fibrosarcomas that arise after injection of ras-transformed cells into nude mice. We propose that transforming genes in plaque cells behave in a manner analogous to the way in which oncogenes behave in cancer cells.

Enhanced in vitro selective toxicity of chemotherapeutic agents for human cancer cells based on a metabolic defect.

Abstract: A metabolic defect that is prevalent in human cancer cell lines was exploited to selectively kill these cells without killing cocultured normal human fibroblasts. Methionine dependence, a metabolic defect seen only in cancer cells or immortalized cell lines in vitro, precludes the cells from growing in media in which methionine is replaced by its immediate precursor, homocysteine, a condition that allows the growth of all normal cell strains tested. The methionine-dependent cells become reversibly blocked in late S-G2 (i.e., late-S and G2 phases) under the above condition, a block that was exploited for selective chemotherapy against these cells. In cultures that were initiated with equal amounts of cancer cells and human diploid fibroblasts, substitution of homocysteine and doxorubicin for methionine in the culture medium followed by methionine repletion with vincristine was totally effective at selectively eliminating a methionine-dependent human sarcoma and 3 methionine-dependent human carcinomas. The above protocol was nearly totally effective against a partially methionine-independent revertant of the sarcoma. The chemotherapeutic procedure used was not lethal to normal cells growing alongside the tumor cells and was ineffective when conducted totally in methionine-containing medium. The optimal procedure was 10(-10) M doxorubicin in methionine-free, homocysteine-containing medium for 10 days followed by 2 x 10(-7) M vincristine in methionine-containing, homocysteine-free medium for 1 day, in turn followed by drug-free methionine-containing, homocysteine-free medium. These results demonstrate the potential for treatment of solid tumors with chemotherapy based on metabolic differences between normal and tumor cells.

Differences in Phosphate Metabolite Levels in Drug-sensitive and -resistant Human Breast Cancer Cell Lines Determined by 31P Magnetic Resonance Spectroscopy

Abstract: 31P magnetic resonance spectra of perfused human breast cancer cells with the phenotype of pleiotropic drug resistance exhibit striking differences in the levels of phosphate metabolites from the wild-type, drug-sensitive parent cell line. Resistant cells demonstrated elevated levels of phosphocreatine and depressed levels of phosphomonoesters, phosphodiesters, and diphosphodiesters. These differences may reflect significant alterations in the control of bioenergetic metabolism between drug-resistant and -sensitive cells.

Cloning of estrogen-regulated messenger RNA sequences from human breast cancer cells.

Abstract: A complementary DNA library was constructed from RNA of estrogen-stimulated MCF-7 cells and screened for estrogen-regulated sequences. Four different messenger RNA sequences of varying abundance were isolated. Two of the sequences (pNR-3 and pNR-4) were induced approximately 2-fold, while the other two (pNR-1 and pNR-2) were induced at least 8-fold. The induction of both pNR-1 and pNR-2 requires similar physiological concentrations of estradiol and is near maximal at 10(-10) M. An increase in the levels of the RNAs is seen after 30 min of estrogen treatment, but pNR-1 reaches its maximal concentration faster than pNR-2. pNR-1 and pNR-2 were not expressed in all human breast cancer cell lines tested. pNR-1 was expressed and regulated by estrogen in the estrogen receptor-positive cell lines, MCF-7, T-47D, and ZR 75, whereas pNR-2 was not expressed in the T-47D cell line. pNR-1 and pNR-2 were not detected in two estrogen receptor-negative cell lines (BT20 and HBL 100). As the proliferation of the MCF-7, T47D, and ZR 75 cell lines is stimulated by estradiol, pNR-1 may provide a useful marker of hormone-responsive breast cancer.

Three alkaloids as selective destroyers of cancer cells in mice. Synergy with classic anticancer drugs.

Abstract: Alstonine, serpentine and sempervirine, when used at appropriate concentrations cure a relatively important proportion of BALB/C mice inoculated with transplantable YC8 lymphoma ascites cells, as well as Swiss mice bearing Ehrlich ascites carcinoma cells. The development of some solid tumors was only partially prevented. However, when one alkaloid was administered in association with either 5-FU, daunorubicin, 1-(2-chloroethyl) nitrosourea (CCNU) or cyclophosphamide (CP) to mice bearing either ascites carcinoma cells or solid tumors, a high rate of cure was obtained without toxicity. The role of the three alkaloids in the curing of mice and prevention of carcinogenesis is discussed.

Control of Cell Proliferation: Evidence for Negative Control on Estrogen-sensitive T47D Human Breast Cancer Cells

Abstract: The human breast tumor cloned cell lines T47D-A8 and All are estrogen dependent for cell proliferation in the nude mouse model. In contrast, these cells multiplied at similar rates when grown in serum-free cultures, regardless of the presence of 17β-estradiol (3 × 10-11 to 3 × 10-8 m estradiol). Addition of 10% charcoal-dextran stripped human female serum to the culture medium resulted in a marked inhibition of cell proliferation. The addition of 3 × 10-11 m estradiol overcame the inhibitory effect of serum. Similar results were obtained with the human breast tumor C7MCF7 cell line. Both cell lines contain similar estrophilin levels. The K d of the estrophilin-estradiol complex was 0.39 × 10-10 m for C7MCF7 cells and 4.4 × 10-10 m for T47D-A11 cells. Maximal cell yields were achieved at 5 × 10-12 m free estradiol levels in 10% charcoaldextran stripped serum supplemented medium. These data are compatible with the following interpretation: ( a ) estradiol-sensitive cells are inhibited from proliferating by a serum-borne factor; and ( b ) estradiol neutralizes this inhibitory effect. This mechanism seems not to be mediated by estradiol binding to the cellular estrophilins because ( a ) the free estradiol levels needed for maximal response are significantly lower than the estrophilin K ds, and ( b ) maximal proliferation rates occur at similar estradiol concentrations for these three cell lines, regardless of the binding properties of their estrophilins.

Epidermal growth factor binding and protein kinase C activities in human breast cancer cell lines: possible quantitative relationship.

Abstract: Quantitative polyacrylamide gel electrophoresis analysis of Ca2+, phospholipid-dependent protein kinase (PKC) of human mammary tumor cell lines (MCF-7, ZR-75, T-47-D, MDA-MB-231, BT-20, and HBL-100) revealed that 80% of the total cellular PKC resided in the cytosol. The tumor cells with no detectable levels of estrogen receptors (MDA-MB-231, HBL-100, and BT-20 cells) exhibited significantly larger ( P < 0.001) cytosolic PKC activities than those cells that contained estrogen receptors (MCF-7, T-47-D, and ZR-75 cells). In addition, in estrogen receptor-negative cell lines, relatively high levels of specific low-affinity (appearent K d = 700 pm) epidermal growth factor (EGF) binding activities were found as compared with estrogen receptor-positive cells with significantly ( P < 0.001) lower levels of specific high-affinity (apparent K d = 90 pm) EGT binding. A significant positive correlation ( P < 0.01) was observed between the number of EGF receptor ( R s = 0.50) and/or the EGF receptor dissociation constants ( R s = 0.78) with the cytosolic PKC activity levels. These data indicate that, in human breast cancer cells, a positive relationship may exist between PKC activity, estrogen, and EGF receptors.

Specific Cytotoxicity of a Long-Term Cultured T-Cell Clone on Human Autologous Mammary Cancer Cells

Abstract: We established an autologous specific T-cell killer clone, TcHMC-1, that has been cultured and has retained its function for over 1 year. TcHMC-1 and target cells (HMC-1-8) were derived from the metastatic pleural effusion of a patient with mammary carcinoma. At culture initiation, pleural exudative lymphocytes (PLEL) already demonstrated a high cytotoxic activity against uncloned HMC-1 breast tumor cell targets but not against autologous fibroblasts and K562 targets, and phenotypically these cells showed 100 and 90% reactivity with OKT3 and OKT8 monoclonal antibodies, respectively. However, at the early phase of cultivation under interleukin 2, PLEL had a relatively high cytotoxicity against some allogeneic tumor cells. Furthermore, the longer these PLEL were cultured with interleukin 2 and stimulated with MMC-treated HMC-1, the less cytotoxic activity of PLEL against HMC-1 targets became. We then cloned PLEL as well as HMC-1 tumor cells, and an autologous pair of TcHMC-1 and a target cell clone, HMC-1-8, was successfully obtained. TcHMC-1 showed more than 60% specific cytotoxicity against HMC-1-8, and it was confirmed, using cold target inhibition assays, that TcHMC-1 did not demonstrate nonspecific cytotoxicity against allogeneic targets as well as the natural killer cell activity. Moreover, we examined the in vivo action of TcHMC-1 against HMC-1-8 cells by the Winn assay using nude mice. The data showed that s.c. injections with a mixture of TcHMC-1 and HMC-1-8 clearly resulted in a failure of tumor development in the nude mice even 12 weeks after injections, whereas mice given injections of HMC-1-8 and allogeneic T-lymphocytes cultured with interleukin 2 developed tumors. The autologous pair of a killer T-cell clone and tumor line could be very useful for future investigations of the specific destruction of autologous tumor cells by cytotoxic T-lymphocytes, including analysis for tumor-specific antigens possibly of rejection type and clonotypic T-cell antigen receptors.

Amiodarone-induced Enhancement of Doxorubicin and 4′-Deoxydoxorubicin Cytotoxicity to Rat Colon Cancer Cells in Vitro and in Vivo

Abstract: The mechanisms of the resistance of intestinal cancer to anthracyclines were studied on an experimental model of rat colon cancer cells. The accumulation of anthracyclines in the nucleus of living cancer cells was observed by fluorescence microscopy. This accumulation depended on both the capacity of anthracyclines to penetrate into the cell and the activity of an efflux mechanism extruding the drug from the cell. We found that 4'-deoxydoxorubicin was superior to 4 other anthracyclines in its capacity to penetrate into confluent colon cancer cells. Amiodarone, an antiarrhythmic agent used in cardiology, inhibited the efflux mechanism efficiently and increased the toxicity of anthracyclines to the colon cancer cells. Association of amiodarone and 4'-deoxydoxorubicin was able to cure 5 of 13 rats that had been inoculated i.p. previously with syngeneic colon cancer cells. This association could be of interest in the treatment of human colon cancer.

Antitumor effects of an immunotoxin made with Pseudomonas exotoxin in a nude mouse model of human ovarian cancer

Abstract: An immunotoxin composed of Pseudomonas toxin coupled to an antibody to the human transferrin receptor was evaluated for its effect on ovarian cancer. In the tumor model employed, 60 million human ovarian cancer cells were injected into the peritoneal cavity of an immunodeficient nude mouse. By day 5, cancer cells were implanted and growing in small clusters throughout the peritoneal cavity. On days 5-8, 0.3-2 micrograms of immunotoxin was injected into the peritoneal cavity. Control mice died with malignant ascites at 34-58 days after the implantation of tumor cells, whereas immunotoxin-treated mice lived to 100 days or longer. Irrelevant immunotoxins or antibody alone had no antitumor activity. These findings suggest that intraperitoneal injection of immunotoxins may have a role in the treatment of ovarian cancer.

Effects of gastrin, glutamine, and somatostatin on the in vitro growth of normal and malignant human gastric mucosal cells.

Abstract: • This study evaluated the dose-related trophic effects of glutamine, gastrin, and somatostatin on the in vitro growth of human gastric cancer cells and normal human gastric mucosal cells. Quadruplicate cell cultures were seeded into growth medium with or without glutamine, gastrin, or somatostatin. After 72 hours' incubation, cells were counted and their numbers compared with those of controls. Glutamine and gastrin stimulated the growth of both normal and malignant gastric mucosal cells. Compared with normal cells, the malignant cells responded to these growth factors at lower concentrations. Somatostatin enhanced growth of gastric cancer cells at all concentrations and inhibited growth of normal cells at high concentrations. Further studies on the responsiveness of gastric adenocarcinoma to gastrointestinal tract hormones may elucidate mechanisms of oncogenesis and suggest new therapeutic avenues for patients with gastric cancer. (Arch Surg1986;121:285-288)