Rat Ascites Hepatoma AH66 Cells Research Articles

Activated peritoneal macrophages inhibit the proliferation of rat ascites hepatoma AH-130 cells via the production of tumor necrosis factor-alpha and nitric oxide.

To study the effect of peritoneal macrophages on tumor cell proliferation, we cultured ascites hepatoma AH-130 cells with unstimulated, or lipopolysaccharide (LPS)- or interleukin (IL)-2-stimulated rat peritoneal macrophages, and examined the proliferation of AH-130 cells. Rat peritoneal macrophages isolated from male Wistar rats were co-cultured with AH-130 cells in the absence or presence of LPS or IL-2. After incubation, proliferation of AH-130 cells was analyzed using flow cytometry. In addition, the levels of tumor necrosis factor (TNF)-alpha and nitric oxide (NOx, nitrate + nitrite) in the culture supernatants were measured. Furthermore, anti-TNF-alpha antibody (10 microg/ml) and nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA, 100 microM) were added to the coculture, and their effect on AH-130 cell proliferation was examined. When AH-130 cells were co-cultured with unstimulated peritoneal macrophages, proliferation of AH-130 cells was not affected. In contrast, when AH-130 cells were cocultured with peritoneal macrophages in the presence of LPS (0.1-20 microg/ml) or IL-2 (1-200 U/ml), proliferation of AH130 cells was dose-dependently suppressed by LPS or IL-2. Moreover, LPS- or IL-2-stimulation increased the levels of TNF-alpha and NOx in the supernatants of AH-130 cell and macrophage co-culture, although LPS and IL-2 did not induce TNF-alpha and NOx production by AH-130 cells incubated without macrophages. Interestingly, anti-TNF-alpha antibody and L-NMMA significantly inhibited the suppression of AH-130 cell proliferation by LPS- or IL-2-stimulated macrophages (p < 0.05). Furthermore, exogenously added recombinant rat TNF-alpha (0.26-1300 ng/ml) or NO donor (GSNO, S-nitroso-L-glutathione) (0.1 - 10 mM) dose-dependently suppressed the proliferation of AH-130 cells in the absence of macrophages. Together these observations suggest that when peritoneal macrophages are activated by LPS and IL-2, they suppress the proliferation of ascites hepatoma AH-130 cells via the production of TNF-alpha and nitric oxide.

Establishment by adriamycin exposure of multidrug-resistant rat ascites hepatoma AH130 cells showing low DT-diaphorase activity and high cross resistance to mitomycins.

A resistant subline (AH130/5A) selected from rat hepatoma AH130 cells after exposure to adriamycin (ADM) showed remarkable resistance to multiple antitumor drugs, including mitomycin C (MMC) and porflromycin (PFM). PFM, vinblastine (VLB), and ADM accumulated in AH130/5A far less than in the parent AH130 (AH130/P) cells. AH130/5A cells showed overexpression of P‐glycoprotein (PGP), an increase in glutathione S‐transferase activity, and a decrease in DT‐diaphorase and glutathione peroxidase activity. The resistance to MMC and VLB of AH130/5A cells was partly reversed by H‐87, an inhibitor of PGP. Buthionine sulfoximine, an inhibitor of glutathione synthase, did not affect the action of MMC. tert‐Butylhydroquinone induced DT‐diaphorase activity, increased PFM uptake, and enhanced the growth‐inhibitory action of MMC in AH130/5A cells. Dicumarol, an inhibitor of DT‐diaphorase, decreased PFM uptake and reduced the growth‐inhibitory action of MMC in AH130/P cells. These results indicated that the adriamycin treatment of hepatoma cells caused multifactorial multidrug resistance involving a decrease in DT‐diaphorase activity.

The Angiogenesis Inhibitor TNP-470 (AGM-1470) Improves Long-Term Survival of Rats with Liver Metastasis

An excellent therapeutic effect of angiogenesis inhibitors on tumor growth or metastasis has been reported, but the sustained antimetastatic effect of these agents has not been studied. We investigated the sustained effect of TNP-470, an angiogenesis inhibitor, in rats with hepatic metastasis following intraportal implantation of rat ascites hepatoma AH-130 cells. TNP-470 was administered subcutaneously at 15 mg/kg (L-TNP) or 30 mg/kg (H-TNP) on alternate days for 2 weeks. The number of liver metastases was significantly reduced in both the L-TNP (85.1 ± 77.6) and H-TNP (31.7 ± 49.6) groups compared to the control group (300.7 ± 100.7) (P< 0.01) at 14 days after the start of treatment. Although all rats in the control group died within 1 month of massive liver metastasis, the L-TNP and H-TNP, respectively, had a survival rate of 82 and 60%, at 4 months (P< 0.001).Absence oftoxicity of TNP-470 at the lower dose,as evidenced by the absence of intraperitoneal or intrapleural bleeding,contributed to a better prognosis in the L-TNP group. Interestingly, a small dormant metastatic focus was found in only 1 of 15 rats surviving for 4 months, whereas metastatic foci were observed in all rats at the end of treatment. These results suggest that the sustained cytostatic effect of TNP-470 on vascular endothelial cells may help to improve long-term survival by reducing the metastatic burden.

Sensitivity to antitumor drugs and vinblastine binding to membrane in rat ascites hepatoma AH66 cells.

Rat ascites hepatoma AH66 cells have lower sensitivity to Vinca alkaloids and anthracycline antibiotics than AH66F cells, a subline of AH66 cells. AH66 cells expressed P-glycoprotein, while the protein was not detectable in AH66F cells. There are two affinity sites for [3H]vinblastine binding in the AH66 cell membrane, while AH66F cells have only one affinity site. The high affinity [3H]vinblastine binding in AH66 cells was inhibited by Adriamycin, verapamil, nicardipine, and reserpine. The high affinity site of the binding may be the multidrug transporter, P-glycoprotein. [3H]Vinblastine binding was not influenced by adenosine 3'-5'-monophosphate (AMP), adenosine triphosphate (ATP), or guanosine triphosphate (GTP). The multidrug resistance in AH66 cells may depend on P-glycoprotein which is not modulated by nucleotide.

Studies on responsiveness of hepatoma cells to catecholamines. VI. Characteristics of adrenoceptors and adenylate cyclase response in rat ascites hepatoma cells and human hepatoma cells.

Alpha 1, alpha 2- and beta-Adrenoceptor densities and catecholamine responsiveness in established hepatoma cells, rat ascites hepatoma AH13, AH66, AH66F, AH109A, AH130 and AH7974 cells and human hepatocellular carcinoma HLF and HepG2 cells, were compared with those in normal rat hepatocytes and Chang liver cells. Alpha 1-Adrenoceptor densities measured by [3H]prazosin bindings were not detected in all hepatoma cell lines. Alpha 2-Adrenoceptor densities measured by [3H]clonidine bindings were also barely detected in hepatoma cell lines except for AH130 cells and HepG2 cells. Regarding beta-adrenoceptor, AH109A, AH130 and AH7974 cells had much more [125I]iodocyanopindolol binding sites than normal rat hepatocytes, although we could not detect the binding in HepG2 cells. Adenylate cyclase of normal rat hepatocyte and Chang liver cells were stimulated by beta 2-adrenergic agonist salbutamol, while the cyclase in hepatoma cells had no beta 2-adrenergic response but a beta 1-type response. These findings indicate that the characteristics of adrenergic response in hepatoma cell lines is very different from that in normal hepatocytes, suggesting a participation in the hepatocarcinogenesis and/or the autonomous proliferation of hepatoma cells.

O-094 - Effect of calmodulin inhibitors on membrane transport of vinblastine in multidrug—resistant rat ascites hepatoma AH66 cells.

O-094 - Effect of calmodulin inhibitors on membrane transport of vinblastine in multidrug—resistant rat ascites hepatoma AH66 cells.

Studies on responsiveness of hepatoma cells to catecholamines. V. Loss of adrenergic response of glycogen phosphorylase in rat ascites hepatoma AH130 cells.

The beta-adrenoceptor-cyclic adenosine monophosphate (AMP) dependent glycogenolytic cascade was examined in normal rat hepatocytes and rat ascites hepatoma AH130 cells. The cyclic AMP content in AH130 cells was half of that in normal hepatocytes, and the cyclic AMP levels in both kinds of cells were clearly increased by isoproterenol (IPN). Cyclic AMP-dependent protein kinase activity was higher in AH130 cells than in normal hepatocytes. Phosphorylase kinase activities in 10000 x g supernatant of normal hepatocytes and AH130 cells were also increased in the presence of cyclic AMP. Phosphorylase a activities in the supernatant of both kinds of cells gradually decreased during incubation with 40 mM glucose at 37 degrees C, and the enzyme activity of normal hepatocytes was completely restored by the addition of Mg2(+)-adenosine triphosphate (ATP), but in the case of the hepatoma cells the recovery was small. The decreased phosphorylase a activity in the hepatoma cells was increased by additional glycogen but did not exceed the level before the incubation. In the case of normal hepatocytes it was not affected by glycogen. This indicates that glycogen contained in the cells influences the activation of phosphorylase; the glycogen content in AH130 cells was far less than in normal hepatocytes. On the other hand, when intact cells were incubated with a high concentration of glucose, phosphorylase a activity in the homogenate of normal hepatocytes was decreased and could be restored by IPN and dibutyryl cyclic AMP, but the enzyme activity in the homogenate of AH130 cells was very low and hardly changed after the incubation and treatment with these agents.(ABSTRACT TRUNCATED AT 250 WORDS)

P-264 - Vinblastine accumulation induced by protein kinase inhibitors in rat ascites hepatoma AH66 cells

P-264 - Vinblastine accumulation induced by protein kinase inhibitors in rat ascites hepatoma AH66 cells

Stimulatory and inhibitory effects of forskolin on adenylate cyclase in rat normal hepatocytes and hepatoma cells.

Forskolin synergistically potentiated adenosine 3',5'-cyclic monophosphate formation by prostaglandin E1 (PGE1) in rat normal hepatocytes freshly prepared by collagenase digestion and rat ascites hepatoma AH66 cells, but dose-dependently inhibited the accumulation by PGE1 in AH66F cells. Forskolin activated adenylate cyclase in a dose-dependent manner in homogenates of all cell lines. In normal hepatocytes and AH66 cells, simultaneous addition of forskolin and other adenylate cyclase activators [isoproterenol (IPN), PGE1, guanosine 5'-triphosphate sodium salt (GTP), 5'-guanylylimidodiphosphate sodium salt (Gpp (NH)p), NaF, cholera toxin, islet activating protein and MnCl2] gave greater than additive responses. On the other hand, in AH66F cells, the effect of forskolin on adenylate cyclase was hardly influenced by GTP, but forskolin diminished the activities induced by high concentrations of GTP to that by the diterpene alone. Forskolin also significantly inhibited the PGE1-stimulated and the guanine nucleotide binding regulatory protein-stimulated activities. Because AH66F cells were insensitive to IPN, the combination with forskolin and IPN gave similar activity to that obtained with the diterpene alone. The effect of forskolin on the activation by manganese ion was neither synergistic nor inhibitory but was additive in AH66F cells. These results suggest that forskolin promotes the interaction between the stimulatory guanine nucleotide binding regulatory protein and the catalytic unit in normal hepatocytes and AH66 cells, but in AH66F cells forskolin interferes with the coupling of the two components of adenylate cyclase.

A comparison of adrenergic receptors of rat ascites hepatoma AH130 cells with those of normal rat hepatocytes

The pharmacological specificity of adrenergic receptors in the plasma membrane of rat ascites hepatoma AH130 cells was compared with that in normal rat hepatocytes. The number of [ 125I]iodocyanopindolol-binding sites was much greater in AH130 cells than in the hepatocytes. We characterized the α-adrenergic receptor subtypes using the α 1-selective ligand [ 3H]prazosin and the α 2-selective ligand [ 3H]clonidine. AH130 cells had fewer prazosin-binding sites than the hepatocytes and about 8 times as many clonidine-binding sites of high affinity. The results showed that the adrenergic receptors in AH130 cells have pharmacological properties that are very different from those of the receptors in normal rat hepatocytes.

Multiform combination effects of smooth muscle relaxants with antitumor agents in rat ascites hepatoma AH66 cells.

At non-cytotoxic concentrations, actions of smooth muscle relaxants except for the action of isoproterenol (IPN) on the effect of vinblastine (VBL) and mitomycin C (MMC) in rat ascites hepatoma AH66 cells resistant to these antitumor agents clearly separated into two groups. IPN hardly influenced the effects of both VBL and MMC. Although verapamil, a calcium-antagonist, and W-7, a calmodulin inhibitor, enhanced the growth-inhibitory effect and uptake of VBL by inhibiting the VBL efflux, these drugs did not influence the effect and uptake of MMC. In contrast, forskolin, an adenylate cyclase activator, db-cAMP, a cAMP analog, and theophylline, a cyclic nucleotide phosphodiesterase inhibitor, potentiated the effect of MMC, but did not influence the effect of VBL. The combination effect of forskolin and db-cAMP might be elucidated from the increase of inward transport of MMC through the action of the intracellular cAMP elevated by these drugs. Theophylline, however, only slightly increased both intracellular cAMP level and MMC uptake into the cells, similar to the action of IPN. We thought that the combination effect of theophylline was effected through its other activity of repair inhibition against AH66 cells, which are resistant to MMC due to their high capacity to repair impaired DNA. Thus, the smooth muscle relaxants used in this study enhanced the growth-inhibitory effect of a distinct antitumor agent through their individual activity against tumor cells.

Multiform Combination Effects of Smooth Muscle Relaxants with Antitumor Agents in Rat Ascites Hepatoma AH66 Cells

At non-cytotoxic concentrations, actions of smooth muscle relaxants except for the action of isoproterenol (IPN) on the effect of vinblastine (VBL) and mitomycin C (MMC) in rat ascites hepatoma AH66 cells resistant to these antitumor agents clearly separated into two groups. IPN hardly influenced the effects of both VBL and MMC. Although verapamil, a calcium-antagonist, and W-7, a calmodulin inhibitor, enhanced the growth-inhibitory effect and uptake of VBL by inhibiting the VBL efflux, these drugs did not influence the effect and uptake of MMC. In contrast, forskolin, an adenylate cyclase activator, db-cAMP, a cAMP analog, and theophylline, a cyclic nucleotide phosphodiesterase inhibitor, potentiated the effect of MMC, but did not influence the effect of VBL. The combination effect of forskolin and db-cAMP might be elucidated from the increase of inward transport of MMC through the action of the intracellular cAMP elevated by these drugs. Theophylline, however, only slightly increased both intracellular cAMP level and MMC uptake into the cells, similar to the action of IPN. We thought that the combination effect of theophylline was effected through its other activity of repair inhibition against AH66 cells, which are resistant to MMC due to their high capacity to repair impaired DNA. Thus, the smooth muscle relaxants used in this study enhanced the growth-inhibitory effect of a distinct antitumor agent through their individual activity against tumor cells.

Enhancement of the Cytotoxic Effect of Mitomycin C by β-adrenergic Stimulants in Rat Ascites Hepatoma AH130 Cells

Among several sympathomimetic drugs, isoproterenol, epinephrine and norepinephrine significantly potentiated the cytotoxic effect and the uptake of MMC into rat ascites hepatoma AH130 cells in in vitro experiments, but salbutamol, tulobuterol and phenylephrine did not. The enhancement of MMC uptake into AH130 cells by isoproterenol and norepinephrine was diminished by propranolol but not by phentolamine. These results indicate that the cytotoxic effect and the uptake of MMC is potentiated by the stimulation of β-adrenoceptors, but not by stimulation of β2- and α-receptors.

The mode of mitomycin C uptake in rat ascites hepatoma AH130 cells

The mode of uptake of mitomycin C (MMC) was examined by use of rat ascites hepatoma AH130 cells. The uptake of MMC into AH130 cells increased in proportion to the cell number and the extracellular concentration of MMC. The uptake was nonsaturable and temperature-dependent but not inhibited by metabolic inhibitors such as ouabain, 2, 4-dinitrophenol, sodium azide or iodoacetic acid. MMC was rapidly metabolized in the cells and its metabolites accumulated with the time of incubation. Intact MMC in the cells was only a little. The uptake of MMC was, however, not affected by the metabolites accmulated in the cells. Amphotericin B potentiated the uptake and cytotoxicity of MMC. On the other hand, dibucaine diminished not only the uptake but also the cytotoxicity of MMC.These results suggest that MMC is taken up into rat ascites hepatoma AH130 cells in an energy-independent manner but the uptake is non-saturable because MMC is rapidly metabolized in the cells.

The action of mitomycin C on the induction of cyclic AMP phosphodiesterase and the development of desensitization of adenylate cyclase by isoproterenol in rat ascites hepatoma AH130 cells.

The treatment of AH130 cells with isoproterenol (IPN) resulted in an increase in the activity of cyclic adenosine 3':5'-monophosphate (cyclic AMP) phosphodiesterase with a low Km value and a decrease in IPN-stimulated activity of adenylate cyclase. The activity of cyclic AMP phosphodiesterase was increased by IPN in a dose-dependent manner and reached a maximal increase at 30 min after the addition of 10(-4)M IPN. The addition of mitomycin C (MMC) at 15 min after the initiation of the treatment with IPN inhibited the increase in the activity of cyclic AMP phosphodiesterase in a dose-dependent manner. The extent of the development of desensitization, which was observed as a decrease in IPN-stimulated activity of adenylate cyclase, was dependent on the treatment time with IPN and the concentration of IPN. Desensitization was also observed as a decrease in prostaglandin E1-stimulated activity but not in basal and NaF-stimulated activity. The combined treatment with IPN and MMC showed a higher IPN-stimulated activity of adenylate cyclase than with a single treatment with IPN. This effect resulted from the enhancement of IPN-stimulated activity of the enzyme by MMC itself. These results show that the treatment of AH130 cells with IPN caused an induction of cyclic AMP phosphodiesterase and the development of desensitization of adenylate cyclase. Since the combined treatment with MMC inhibited both phenomena, the high intracellular cyclic AMP level appeared to be maintained by the combined treatment for a longer term than by a single treatment with IPN.

Effect of mitomycin C on the activation of adenylate cyclase in rat ascites hepatoma AH130 cells.

Isoproterenol (IPN)-stimulated activity of adenylate cyclase was enhanced in a dose-dependent manner by exposure of AH130 cells to mitomycin C (MMC). The enhancement was also observed in prostaglandin E1-, guanine nucleotide analog-, NaF-, cholera toxin- and forskolin-stimulated activities of the enzyme but not in manganese-stimulated activity. In addition, even when the cells pretreated with islet-activating protein were exposed to MMC, IPN-stimulated activity of adenylate cyclase was enhanced. Anaerobic exposure of AH130 cells to MMC somewhat inhibited IPN-stimulated activity of adenylate cyclase in contrast with aerobic exposure. Exposure of cells to adriamycin also caused enhancement of IPN-stimulated activity of adenylate cyclase but exposure to nitrogen mustard inhibited the enzyme stimulation by IPN. The enhancing effect of MMC was lost by the combined treatment with alpha-tocopherol. From these results, it was shown that MMC modulated the activity of adenylate cyclase, probably through alterations in membrane structure.

Effects of o-phenanthroline, 2,2'-dipyridyl and neocuproine on the activities of bleomycin to inhibit DNA synthesis and growth of cultured cells.

Effects of o-phenanthroline, 2,2'-dipyridyl and neocuproine, which form stable complexes preferentially with Fe(II), Fe(II) and specifically with Cu(I), respectively, on the inhibitory activity of bleomycin against DNA synthesis of rat ascites hepatoma AH66 cells were examined. The inhibitory activity of metal-free bleomycin was suppressed in the presence of o-phenanthroline or 2,2'-dipyridyl, but not by neocuproine, though these chelating agents also showed the inhibitory activity against the DNA synthesis of the cells by themselves alone. The activity of bleomycin-Cu(II) was also suppressed by o-phenanthroline, but bleomycin-Fe(II) and bleomycin-Fe(III) exhibited some activities in the presence of o-phenanthroline. The growth inhibitory activity of bleomycin against HeLa cells was also suppressed by o-phenanthroline. From these results, bleomycin-iron complexes were suggested to be responsible to the bleomycin action in cells.

The inhibitory effects of horse anti-rat AFP antiserum on the uptake of 2-deoxy-D-glucose by AFP-producing rat hepatoma cells.

The inhibitory effects of horse antiserum against rat alpha-fetoprotein (AFP) on the uptake of 2-deoxy-D-glucose (2dG) by the AFP-producing rat ascites hepatoma AH66 cells was studied. AH66 cells cultured in medium containing 20% heat-inactivated antiserum had a 1.5-fold lower rate of sugar uptake than did AH66 cells which were cultured in medium containing 20% heat inactivated normal horse serum. The inhibition of 2dG uptake by antiserum was dependent on both the concentration and the exposure time of antiserum. Preincubation of AH66 tumor cells for 2 and 6 h with antiserum prior to the measurement of 2dG uptake resulted in a 70.1% and 58.2% decrease in 2dG uptake compared to control cells. Antiserum did not inhibit the rate of phosphorylation of 2dG by tumor cells. Kinetic constants for the uptake of 2dG in both AH66 cells treated with antiserum to AFP and in control cells were calculated from Lineweaver-Burk plots. The Km remained constant at approximately 1.2 mM, but the Vmax was twice as small for the cells treated with antiserum as for the control cells (571 vs 923 nanomoles/2 X 10(5) cells/min). These studies suggest that the inhibition of 2dG uptake by treatment with antiserum was the result of a decrease in the number of transport sites, or a decrease in the amount of carrier protein for the sugar which was present on the surface of the plasma membrane of the AH66 cells.

Amiloride and glucose effects on the intracellular pH of Yoshida rat ascites hepatoma AH-130 cells grown in vivo

The equilibrium distribution of 5,5-dimethyloxazolidine-2,4-dione (DMO) between intra- and extracellular volume was used to estimate the intracellular pH in Yoshida rat ascites hepatoma AH-130 cells under different growth conditions (log, midlog and stationary). The cells were suspended in a Krebs-Ringer 25 mM phosphate buffer and the effects of variation of external pH, of glucose and amiloride addition on intracellular pH were measured. Proliferating cells had higher intracellular pH than stationary phase cells and this difference was inhibited by amiloride. On addition of glucose the fall in external pH was similar in all conditions and corresponded to lactate production. However, the intracellular pH decreased only in proliferating cells. Stationary phase cells showed an amiloride-sensitive cytoplasmic alkalinization with glucose. Glucose addition also caused prompt recovery to a normal polysomal pattern in these cells that might suggest increased efficiency of the initiation step of protein synthesis under these conditions. The data thus suggest that the increased intracellular pH of proliferating and of glucose-treated stationary phase cells is linked to the rate of protein synthesis and is mediated by the amiloride-sensitive Na +/H + exchange system. This could lead to increased intracellular Na + concentration under these conditions and to initiation of growth.

Synthesis of native 60S and 40S ribosomal subunits in Yoshida rat ascites hepatoma AH-130 cells: Correlation with the rate of cell growth

The 60Sn and 40Sn subunit ribosome synthesis declined significantly in Yoshida rat ascites hepatoma AH-130 cells from the log phase to the plateau phase of the in vivo growth. Two main classes of 40Sn particles with protein/RNA ratios of 1.82 (p2) and 1.20 (p3) and a minor “heavy” one with protein/RNA ratio of 0.96 (p1) could be distinguished reproducibly by their ultraviolet absorption after sucrose zone sedimentation. The p2 particles appeared the dominating class in log phase cells. In plateau phase cells a decrease of p2 and an increase of p3 particles was observed. Under these conditions the p1 particles and the peaks corresponding to 60Sn subunits and to 80S ribosomes were also increased. Newly synthetized 40Sn particles banded in the p3 region of the gradient and p2 particles originated from them. These particles entered into the ribosomal cycle and contained poly(A) RNA. Formation of radioactive 80S couples by subunits entering into the ribosomal cycle was markedly stimulated in log phase cells and almost completely blocked in cells at the plateau phase of growth.