Effects of deuterium oxide (D2O) on the development of hypertension and Ca2+ homeostasis in spontaneously hypertensive rats.

Increased calcium uptake in vascular tissues, leading to elevated cytosolic free calcium, has been implicated in the pathophysiology of hypertension. In this study we investigated the in vitro effect of deuterium oxide (D2O) on calcium uptake in Sprague-Dawley (SD) rat aortae as well as the effects of 25% D2O, orally administered to spontaneously hypertensive and Wistar-Kyoto (WKY) rats, on systolic blood pressure and aortic calcium uptake. The high calcium uptake induced by phenylephrine (50 mumols/l) via receptor-operated channels and by KCl (80 mmol/l) via voltage-operated channels in SD rat aortae was effectively reduced by D2O in a concentration-dependent manner. These results suggest that D2O, acting like a calcium channel blocker, effectively normalized vascular calcium uptake mechanisms. When, at 7 weeks of age, spontaneously hypertensive rats were given 25% D2O in their drinking water for a period of 6 weeks, the development of high systolic blood pressures and the associated increases in aortic calcium uptake were effectively prevented. D2O treatment did not affect blood pressures in normotensive WKY rats. The parallel increases in systolic blood pressure and in vascular calcium uptake suggest that increased calcium uptake mechanisms are associated with hypertension. Furthermore, D2O appears to prevent hypertension by normalizing calcium uptake in vascular smooth muscle.

Migration patterns and functional activity of cloned cytotoxic T lymphocytes in syngeneic and allogeneic mice.

The quantitative distribution of cytolytic T lymphocytes (CTL) generated in mixed leukocyte culture (MLC) and an interleukin-2 (IL-2)-dependent, CTL clone (WRL-A3) was investigated in various tissues of irradiated syngeneic and allogeneic mice. In addition, the ability of the WRL-A3 CTL clone to remain viable and retain antigen specificity following in vivo passage was evaluated. Injection i.v. of 51Cr-labeled cultured CTL resulted in: (1) extensive deposition of cells in the lungs with significantly more lymphocytes being recovered in allogeneic as compared with syngeneic lung tissue; (2) minimal accumulation in spleen with more in syngeneic than in allogeneic tissue; and (3) no localization in blood, femurs, thymus, or lymph nodes. The migration rate of cultured CTL exiting the lung during the first 4 hr was markedly faster in syngeneic than in allogeneic recipients and was directly associated with the distribution of these cells in other tissues at 24 hr. The WRL-A3 CTL clone recovered from irradiated syngeneic and allogeneic lung tissue at 1, 3, 6, 8, and 13 days after i.v. injection remained viable, even though no exogenous IL-2 was administered to the recipient mice. The recovered cells proliferated when recultured with IL-2, and retained their antigen specificity for Qed-1b target cells after in vivo passage. These findings indicate that restricted and undesirable tissue distribution, rather than impaired viability or loss of antigenic specificity, is the major obstacle to successful use of cultured CTL for adoptive immunotherapy of disseminated cancer.

Sanguinarine induces bimodal cell death in K562 but not in high Bcl-2-expressing JM1 cells.

Our previous studies with low Bcl-2-expressing K562 cells have shown that, when treated with the putative anti-cancer drug sanguinarine, concentrations of 1.5 microg/ml induced the morphology of apoptosis or programmed cell death (PCD), while concentrations of 12.5 microg/ml induced a morphology of blister formation or blister cell death (BCD). To elucidate the possible role of Bcl-2 in this dual cell death modality induced by sanguinarine, K562 and the high Bcl-2-expressing JM1 cells were treated with sanguinarine concentrations of 1.5 microg/ml and 12.5 microg/ml respectively, and multiple parameters of their effects were studied using light and electron microscopy, terminal deoxynucleotidyl transferase (TdT) end-labeling, 51Cr release, trypan blue exclusion, propidium iodide exclusion, and annexin-V binding. In general, we found that, while K562 cells underwent PCD and BCD when treated with sanguinarine, JM1 cells failed to undergo either PCD or BCD under the same experimental conditions. Thus, the over-expression of anti-apoptotic Bcl-2 may have prevented sanguinarine from inducing PCD and BCD in JM1 cells. These results indicate that the resistance of JM1 cells to the alkaloid sanguinarine may have been due to an anti-BCD role played by Bcl-2, in addition to its widely reported anti-apoptotic role.

Modulation of immune effector cell cytolytic activity and tumour growth inhibition in vivo by Ukrain (NSC 631570).

Ukrain is a semisynthetic compound consisting of alkaloids from Chelidonium majus L. conjugated to thiophosphoric acid, with immunomodulatory and therapeutic properties in cancer patients. The present in vitro studies demonstrate that Ukrain is an effective biological response modifier augmenting, by up to 48-fold, the lytic activity of splenic lymphocytes obtained from alloimmunized mice. The lytic activities of interleukin-2 (IL-2) treated spleen cells and peritoneal exudate lymphocytes were also significantly increased by the addition of Ukrain to the cell mediated lysis (CML) assay medium. The highest Ukrain-induced enhancement of splenic lymphocytolytic activity in vitro was found to occur at day 18 after alloimmunization was dose-dependent and specific for the immunizing P815 tumour cells. Since Ukrain was present only during the CML assays, its mode of action is thought to be via direct activation of the effector cells' lytic mechanism(s). The effect of Ukrain on the growth of Balb/c syngenic mammary adenocarcinoma was also evaluated. Intravenous, but not subcutaneous or intraperitoneal, administration of this drug was found to be effective in delaying tumour growth in an actual therapeutic protocol initiated five days after tumour implantation. No deleterious side-effects were observed using these in vivo treatment modalities. The role of macrophages in the observed retardation of tumour development was investigated, using peritoneal exudate macrophages (PEM) in cytotoxicity assays. Previous studies showed that PEM of mammary tumour-bearing mice lose their capacity to kill a variety of tumour target cells including the in vitro cultured homologous tumour cells (DA-3). Pretreatment of PEM from normal mice with 2.5 microM Ukrain for 24 h, followed by stimulation with either IFN-gamma or with lipopolysaccharide (LPS) plus IFN-gamma enhanced their cytotoxic activity. Treatment of PEM from tumour-bearing mice with 2.5 microM Ukrain and LPS results in a reversal of their defective cytotoxic response against DA-3 target cells. Furthermore, Ukrain alone, in the absence of a secondary signal, induced the activation of tumouricidal function of PEM from tumour-bearing, but not from normal, mice. These data indicate that Ukrain's in vivo effects against the development of mammary tumours may be due, at least in part, to its ability to restore macrophage cytolytic function.

Mitogenic properties of Ukrain (NSC-6315170) on human peripheral blood monocytes: clinical implications.

Using a cell-proliferation assay, the authors examined and compared the mitogenic effects of Ukrain and phytohaemagglutinin (PHA) on human peripheral blood mononuclear cells (PBMCs), as well as their synergic effects. It was found that even a short period of pretreatment of the cell with Ukrain had a potent synergic effect on PHA mitogenesis resulting in significantly higher cell stimulation indices than those of PHA alone. Moreover, it was found that a short period of PHA treatment of the cells is almost imperative for Ukrain to exert its mitogenic effects. The mitogenic effect of Ukrain on human PBMCs is consistent with a previous clinical report which found that circulating lymphocytes were significantly increased in cancer patients treated with Ukrain. Thus the in vitro assay used in these studies may serve as a prognostic assay for potential patient responsiveness to Ukrain treatment, as well as a clinical parameter during Ukrain therapy.

Influence of Ukrain on immunological blood parameters in vitro and in vivo.

Immunological changes are often seen in subjects suffering from oncological disease. Decreased NK activity, alterations of the T4/T8 quotient, decreased phagocytic activity, low reactivity and decreased recognition of the "foreign" are common features seen in these patients. Cytostatic therapy (chemotherapy and radiation therapy) very often enhance these negative properties, thus limiting therapeutic possibilities by highly toxic sequels. Ukrain, being cytostatic and immune-stimulating and modulating, has no adverse effects on the organism.

Induction of bimodal programmed cell death in malignant cells by the derivative Ukrain (NSC-631570).

Selective induction of malignant cell death is one of the major goals of effective and safe chemotherapy. Recent developments in the understanding of programmed cell death (PCD) or apoptosis are expected to provide new leads for a safer chemotherapy. The authors investigated whether the semisynthetic alkaloid thiophosphoric acid derivative Ukrain (NSC-631570) could induce PCD or apoptosis in human K562 leukaemia cells. Results showed that Ukrain induced two distinct modalities of cell death programmes. One modality corresponded morphologically to classical apoptosis or PCD characterized by blebbing and shedding of membrane vesicles with concomitant 51Cr release; however, the Ukrain-induced apoptosis was not associated with the characteristic nuclear DNA fragmentation. Higher concentrations of Ukrain induced a second cell death programme characterized by cell surface blister formation, high specific 51Cr release and extensive DNA polyploidy. These two cell death programmes are distinct from each other in that they are interphased by a silent period characterized by normal cell morphology and reduced specific 51Cr release.

Influence of Ukrain on DNA, RNA and protein synthesis in malignant cells.

3H labelled thymidine, uridine and leucine were used to evaluate the synthesis of DNA, RNA and proteins in malignant cells and normal cells incubated with Ukrain in different concentrations. Compared with the controls, the inhibiting effects of Ukrain are demonstrated in guinea pig hepatocytes, CIL hepatocytes, human tonsil cells, two murine lymphomas, murine myeloma, Yoshida cells, two HeLa strains, EsB- and EB- (murine) lymphomas. YAC-1, P815 and human WiDr cells. Ukrain inhibits the DNA, RNA and protein synthesis in malignant cell lines at relatively high concentrations and to a small extent in normal cells.

Influence of Ukrain on human xenografts in vitro.

Tumour cells were taken from human tumour xenografts (HTX) and serially transplanted into nude mice. These cells were used in a colony-forming assay in vitro. Tumour cells were incubated continuously for at least one week with several concentrations of the drug Ukrain. This was done with six different types and the colony formation was scored for each tumour. The drug effects were reported as percent T/C (Test/Control) for the numbers of colonies formed. Activity is considered to be present at T/C < 30%. A clear dose-response effect was found for Ukrain.

Potential therapeutic efficacy of Ukrain (NSC 631570) in AIDS patients with Kaposi's sarcoma.

In this study two case reports are presented of therapy with Ukrain, a semi-synthetic thiophosphoric acid compound of alkaloids isolated from Chelidonium majus L, for the treatment of AIDS patients with Kaposi's sarcoma. Ukrain was injected i.v. in the dose of 5 mg every other day for a total of 10 injections. During treatment the Kaposi's sarcoma lesions diminished in size, showed decolouration and no lesion appeared in the 30-day interval after the beginning of treatment. Both patients tolerated Ukrain well and showed an improved immunohaematological status: an increase in total leukocytes, T-lymphocytes and T-suppressor numbers. In one case T-helper lymphocytes were also increased. Future investigations are necessary for the evaluation of Ukrain efficacy in the treatment of this type of patients.

Selective inhibition of in vitro cell growth by the anti-tumour drug Ukrain.

The inhibitory effect of Ukrain on malignant cells and on normal cells, in vitro, has been compared. To obtain a 50% inhibition of cell growth, a tenfold concentration had to be used with normal endothelial cells compared to a human osteosarcoma cell line. Hybrids of the two cell types showed nearly the same sensitivity as normal cells. A laser scanning microscope showed a high uptake of Ukrain in malignant cells, while the content in normal cells under the same experimental conditions was substantially lower.

Enhancement of macrophage tumouricidal activity by the alkaloid derivative Ukrain. In vitro and in vivo studies.

Ukrain is a semisynthetic drug with immunomodulatory properties, derived from Chelidonium majus L. alkaloids and thiophosphoric acid. The effect of this compound on the growth of Balb/c syngenic mammary adenocarcinoma was assessed. Intravenous, but not subcutaneous or intraperitoneal, administration of this drug was found to be effective in delaying tumour growth in an actual therapeutic protocol initiated five days after tumour implantation. No untoward side-effects were observed using these in vivo treatment modalities. The role of macrophages in the observed retardation of tumour development was investigated using peritoneal exudate macrophages (PEM) in cytotoxicity assays. In previous studies, the authors have found that PEM of mammary tumour bearing mice lose their capacity to kill a variety of tumour target cells including the in vitro cultured homologous tumour cells (DA-3). Pretreatment of PEM from normal mice with 2.5 microM Ukrain for 24 h followed by stimulation with either IFN-gamma or with LPS+IFN-gamma enhanced their cytotoxic activity. Treatment of PEM from tumour bearing mice with 2.5 microM Ukrain and LPS results in a reversal of their defective cytotoxic response against the DA-3 target cells. Furthermore, Ukrain alone, in the absence of a secondary signal, induced the activation of tumouricidal function of PEM from tumour bearing but not from normal mice. These data indicate that Ukrain's in vivo effects against the development of mammary tumours may be due, at least in part, to its ability to restore macrophage cytolytic function.

Possible role of microtubules in tumor cell surface membrane shedding, permeability, and lympholysis.

Low temperature (0 degrees C/1 hr) induced changes in the mastocytoma P815 cell surface morphology which mimicked those induced by alloimmune T-lymphocytes during the cytolytic process. These morphological changes consist of the formation and shedding of membrane vesicles (MV) from the P815 cell surface. When the low-temperature-induced MV shedding process takes place at 22 degrees C, it occurs without changes in membrane permeability to 51Cr, whereas at 37 degrees C, the kinetics of 51Cr release resemble those induced by alloimmune T lymphocytes. The effects of two microtubule-stabilizing agents, deuterium oxide and hexylene glycol, were investigated on the low-temperature-induced MV shedding process as well as on the lymphocyte-mediated cytolysis (LMC) of target cells. These agents were found to inhibit (a) the low-temperature-induced MV shedding, (b) the low-temperature-induced membrane permeability changes to 51Cr, and (c) the LMC process. These data indicate that disruption of microtubules may be involved in all these events.

Morphological, physiological and biochemical parameters associated with cell injury: a review.

Various forms of cellular injury, whether induced by immune effector cells, aberrant metabolic processes, chemotherapeutic drugs or temperature shifts, result in common morphological changes consisting of the formation and shedding of membrane vesicles from the injured cell surfaces. This dynamic cell surface membrane behavior appears to be dependent on the disruption of cytoplasmic microtubules. Concomitant with the altered cell surface morphology certain physiological and biochemical events have been found to be associated with cell injury. These include changes in membrane permeability, elevated oxygen consumption rates and nuclear DNA fragmentation. However, it remains to be experimentally established which of these biological changes defines a state of irreparable cell injury. The objective of the present review is to compare and evaluate the cell injury process induced by effector lymphocytes with that caused by low temperature. The latter mimics most, if not all, the currently known criteria of immune effector cell mediated injury of target tumor cells.

Kinetic analysis of K+ ion channel function in lymphokine-activated killer (LAK) cells.

K+ ion channels of lymphocytes have been implicated in cellular differentiation, activation and cytolytic functions. We previously demonstrated that K+ channel blockers modulate lytic activity of CTLs and LAK cells. In the present study, we define and quantitate the inhibitory effects of ion channel blockers on the lytic process using kinetic analysis of lysis. The K+ channel blocker, 4-aminopyridine, the neuroendocrine monoamine, serotonin, its agonist, quipazine, and the Ca++ dependent K+ channel blocker, quinidine were found to non-competitively inhibit the lytic process in a dose-dependent manner. These compounds inhibit lytic activity by causing a decrease in the maximum velocity (Vmax) by which LAK cells lyse tumor targets. These ion channel blockers did not alter effector or target cell viability or the binding of LAK cells to tumor cells. The inhibitory effects occurred at the effector cell level, since preincubation of LAK effector cells resulted in a dose-dependent decrease in Vmax which was related to a slower rate of target cell lytic programming (k2) by the LAK effector cells. Modulation of LAK cell lytic function occurs at a post-binding step, perhaps in the generation or release of the lytic signal.

Oxygen consumption by tumor cells during membrane vesicle shedding.

The incubation of mastocytoma P815 cells at low temperature (0 degrees C/1-2 hr), with a subsequent shift to greater than or equal to 20 degrees C results in the formation and shedding of membrane vesicles from the tumor cell surfaces. This process, when occurring at physiologic temperature (37 degrees C), mimics the morphological and membrane permeability changes occurring during T-lymphocyte mediated cytolysis of tumor cells. The latter is an oxygen dependent event, but it is not known whether this requirement is at the effector T cell or at the tumor cell level. The present study investigated the oxygen consumption rates of mastocytoma P815 cells induced to shed membrane vesicles by a temperature shift (0 degrees C/1-2 hrs----greater than or equal to 20 degrees C). Results showed that cells undergoing the membrane vesicle shedding process had significantly higher oxygen requirements than control non-shedding cells. Inhibition of the shedding process with deuterium oxide and hexylene glycol, reduced the oxygen consumption rates of low temperature treated cells to the level of control cells. The oxygen consumption rates of the latter were unaffected by these microtubule stabilizing agents. These data indicate that the oxygen required for immune T-cell mediated lysis of tumor cells may be at the target tumor cell level.

Role of K+ ion channels in lymphokine-activated killer (LAK) cell lytic function.

Cells of the immune system possess K+ ion channels which have been implicated in various cellular functions including activation, differentiation and cytolytic function. To define the role of K+ ion channels in the lytic function of lymphokine-activated killer (LAK) cells, we investigated the effects of K+ channel blockers on their cytolytic activity. Results show that when LAK cell mediated cytolysis of AKIL-20 tumor cells was carried out in the presence of: a) the K+ channel blocker, 4-aminopyridine (4-AP); b) the monoamine, serotonin (5-hydroxytryptamine; 5-HT); c) the serotonin agonist, quipazine; d) or the Ca++ dependent K+ channel blocker, quinidine, the cytolytic activity of the LAK cells was inhibited in a dose-dependent manner. Preincubation of LAK effector cells also inhibited lysis in a dose-dependent manner, whereas preincubation of the AKIL-20 tumor target cells produced no inhibitory effects. This study demonstrates that K+ ion channels are involved in the LAK cell cytolytic process and that compounds, including neuroendocrine products, which modulate K+ ion channel function are capable of modulating the lytic activity of these effector cells.

Shedding of tumor cell surface membranes.

Mastocytoma P815 cells are induced to form and shed membrane vesicles (MV) from their surfaces by incubation at low temperature (4 degrees C) for 1 hr. and subsequently allowing them to warm up to room temperature (22 degrees C). Within 1-2 hrs. at room temperature, up to 90% of the P815 cells form and shed MV from their surfaces. Both cells and vesicles remain trypan blue-excluding during the MV shedding process. This process is energy dependent in that it can be inhibited by 2-deoxyglucose, sodium azide and 2-4-dinitrophenol. The shed MV can be harvested by centrifugation on a 6% Ficoll cushion and quantitated in terms of protein content. The shedding of membrane vesicles from the tumor cell surfaces results in a significant reduction in the cell size.

Low temperature-induced cell surface membrane vesicle shedding is associated with DNA fragmentation.

Temperature shift conditions of 0 degree to 22 degrees C or 0 degree to 37 degrees C induce the formation and shedding of membrane vesicles (MV) from P815 tumor cell surfaces. When the MV shedding process takes place at 22 degrees C it occurs without changes in cell surface membrane permeability, whereas at 37 degrees C, changes in permeability to 51Cr and trypan blue do occur, thus mimicking the lymphocyte-mediated lytic process of tumor cells [1]. The present studies demonstrate that nuclear DNA fragmentation also occurs in both 0 degree to 22 degrees C and 0 degree to 37 degrees C temperature shifts but cell surface membrane permeability to DNA fragments occurs only in the latter condition, i.e., 0 degree to 37 degrees C. The microtubule-stabilizing agent deuterium oxide (D2O) inhibited the MV shedding process, the changes in membrane permeability, and DNA fragmentation. When P815 cells which had been induced to shed MV by the 0 degree to 22 degrees C temperature shift were labeled with 51Cr and used as targets for alloimmune lymphocytes, they were found to be as susceptible to T-cell lysis as control P815 cells. This result indicates that the lytic effect of alloimmune T lymphocytes can be exerted at the target cell surface membrane level independently of nuclear DNA fragmentation.

A possible role for K+ channels in tumor cell injury. Membrane vesicle shedding and nuclear DNA fragmentation.

Mastocytoma P815 tumor cells subjected to low temperature (O degrees C/l h) and shifted to 22 degrees or 37 degrees C undergo morphological, physiological and biochemical changes which are analogous to those induced by immune effector cells, i.e., changes in cell-surface morphology and membrane permeability, elevated O2 consumption rates and nuclear DNA fragmentation [18-21]. Utilizing this low-temperature shift method for the induction of cell injury, we investigated the possible role of K+ channels in this process. Results show that the two classical K+ channel blockers, tetraethylammonium (TEA) and 4-aminopyridine (4-AP), inhibited the low temperature-induced cell-surface membrane vesicle shedding as well as the nuclear DNA-fragmentation process. These results indicate that K+ channel function is required for tumor-cell injury as manifested by nuclear DNA fragmentation and cell-surface membrane vesicle (MV) shedding.