Induction of glucagon sensitivity in a transformed kidney cell line by prostaglandin E2 and its inhibition by epidermal growth factor.

A model system using a transformed dog kidney cell line (Madin-Darby canine kidney), has been established for studying the process of differentiation. Glucagon responsiveness can be restored to these transformed cells by various differentiation inducers, including prostaglandin E2. Glucagon response was measured in terms of the ability of glucagon to stimulate cAMP production. Induction of glucagon sensitivity seems to be mediated by cAMP. The ability of various prostaglandin analogs to elevate the cAMP level correlates closely with their ability to induce glucagon sensitivity. In fact, 8-Br-cAMP is also a potent inducer. To define the nature of this cAMP-mediated process, we identified several inhibitors of this induction process. These differentiation inhibitors include serum, phorbol ester, and epidermal growth factor. These inhibitors do not have a direct effect on cAMP production by cells in the presence or absence of hormones. Furthermore, induction by 8-Br-cAMP is also inhibited by these agents. Therefore, the site of inhibition is located beyond the point of cAMP production. Possible interaction between cAMP- and epidermal growth factor-dependent phosphorylations is discussed.

Intraperitoneal lymphokine-activated killer cell/interleukin-2 therapy in patients with intra-abdominal cancer: immunologic considerations.

Lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2) were administered by the ip route to patients with intra-abdominal malignancies. Pharmacokinetic studies of IL-2 revealed 10- to 100-fold higher concentrations of IL-2 in peritoneal fluid versus serum. Ip levels of IL-2 were maintained well above those required to generate and maintain LAK cells in vitro. LAK cell activity was detectable in the peritoneal fluid for the duration of each treatment cycle and did not disappear until IL-2 was discontinued. Detection of interferon-gamma (IFN-gamma) in the peritoneal fluid of all patients was consistent with production in situ by activated lymphocytes. In some patients, low but detectable levels of IFN-gamma were also found in the serum. In vivo activation of monocytes in the peritoneal fluid as measured by in vitro production of hydrogen peroxide was documented in the majority of patients. Neither interleukin-1 nor tumor necrosis factor-alpha was detected in the peritoneal fluid. We found no correlation between the presence or levels of IL-2, IFN-gamma, or LAK cell lytic activity in peritoneal fluid or serum and response or nonresponse to therapy.

Lymphokine-activated killer cells: culture conditions for the generation of maximal in vitro cytotoxicity in cells from normal donors.

The current method for generating lymphokine-activated killer (LAK) cells for use in human clinical trials is both labor intensive and expensive. Therefore, we altered cell culture conditions to determine whether LAK cells with enhanced lytic activity could be generated. Culture of normal human peripheral blood leukocytes for 7 days generated LAK cells with 4-fold more lytic activity than culture for 3 days. Although cell viability over this 7-day period dropped from 94% on Day 3 to 73% by Day 7, the recovery of cells from culture increased from 61 to 106%. If cells were exposed to CO2, lytic activity was further enhanced by up to 30-fold. Culture at a density of 1 or 2.5 X 10(6) cells/ml caused no difference in cell viability, recovery, or LAK activity when cells were cultured for up to 4 days; however, when cells were cultured for longer times, an initial density of 1 X 10(6) cells/ml yielded maximal LAK activity. Several commercially available serum-free defined media as well as human serum albumin supported LAK cell activation comparable to serum-containing media over a 4-day culture period. One defined medium, AIM V, supported LAK cell activation over a 7-day period even when cells were cultured at a density twice as high (2 X 10(6) cells/ml) as cells cultured in serum-containing medium. The results demonstrate that simple manipulation of human LAK cell culture conditions generates cells with greatly enhanced lytic activity and that serum-containing medium may not be necessary for generating LAK cells under the current clinical protocols.

Cytokine gene expression during the generation of human lymphokine-activated killer cells: early induction of interleukin 1 beta by interleukin 2.

Culture of human peripheral blood leukocytes with interleukin 2 (IL-2) stimulates their differentiation into lymphokine-activated killer (LAK) cells, with a broad range of cytotoxicity against fresh tumor cells and tumor cell lines (Grimm et al., J. Exp. Med., 155: 1823-1841, 1982). We chose to utilize a molecular approach to determine whether IL-2 stimulates the expression of cytokine genes by the mixed cell population which may be involved in the generation or regulation of lytic activity. Northern blot analysis performed with total cellular RNA from LAK cells cultured for varying periods of time with IL-2 revealed that the genes which code for cytokines [interleukin 1 (IL-1)alpha and beta, gamma-interferon, tumor necrosis factor alpha, and lymphotoxin] were not spontaneously expressed. As soon as 2 h after IL-2 treatment, IL-1 alpha and IL-1 beta mRNAs were expressed. Both nonadherent and adherent populations of LAK cells express IL-1 beta mRNA; however, the adherent population produced more IL-1 beta mRNA and maintained its expression for a prolonged period of time. Other cytokine mRNAs (gamma-interferon, tumor necrosis factor alpha, and lymphotoxin) were expressed later than the IL-1 mRNAs with maximal levels between Days 2 through 7. Our results indicate that LAK cell populations can generate a variety of cytokines which may be involved in the generation of lytic activity.

Regulatory states of adenylate cyclase in RL-PR-C cloned rat hepatocytes.

The adenylate cyclase of cloned differentiated rat hepatocytes (RL-PR-C) is regulated by cholera toxin, guanine nucleotides and fluoride. The activation of hepatic adenylate cyclase by cholera toxin was additive with that by GTP and synergistic with that by epinephrine. In contrast, when membranes were exposed to cholera toxin in the presence of Gpp(NH)p or fluoride, the response was the same as to these agents in the absence of cholera toxin. Cholera toxin-activated membranes were responsiveness only to epinephrine and GTP, while fluoride-activated membranes responded somewhat to all other agents, and Gpp(NH)p-activated membranes responded to no other agents. These data suggest that responsiveness of hepatic adenylate cyclase to cholera toxin, fluoride and Gpp(NH)p cannot be expressed simultaneously. A model is presented to explain these observations which invokes multiple states of adenylate cyclase, each being sensitive to, or brought about by, a different regulatory agent.

Endogenous and cholera toxin-catalyzed ADP-ribosylation of a plasma membrane protein by RL-PR-C cloned rat hepatocytes.

Cholera toxin catalyzed the ADP-ribosylation of a single plasma membrane protein (Mr 55 000) of both RL-PR-C rat hepatocytes and purified rat liver plasma membranes. Labeling of this protein from nicotinamide [2,8-3H]adenine dinucleotide was competitively inhibited by free arginine, but by no other amino acid tested, including lysine. The same protein was ADP-ribosylated from NAD+ endogenously, i.e., in the absence of toxin. This process was, however, not competitively inhibited by added arginine nor by any other amino acid tested lysine. Free ADP-ribose, even in 50-fold molar excess over the nicotinamide [2,8-3H]adenine dinucleotide substrate, did not reduce (by isotope dilution) the endogenous or cholera toxin-catalyzed labeling of the 55 000 dalton membrane protein. It is likely, therefore, that hepatocyte plasma membranes contain an ADP-ribosyltransferase, with a mechanism similar to that of the A subunit of cholera toxin, in that both transfer ADP-ribose to the same membrane protein and in that neither apparently produce free ADP-ribose as an intermediate. It is also clear that the acceptor residue in the 55 000 dalton protein is different for each process. Cholera toxin-catalyzed and endogenous transfer of ADP-ribose to the hepatocyte plasma membrane protein, in contrast to a pigeon erythrocyte system, required no cytosolic factors. The results indicate that ADP-ribosylation in cloned differentiated rat hepatocytes differs from that in pigeon erythrocytes in that the acceptor protein is larger (55 000 compared to 42 000 daltons), cytosolic factors are not required and transfer of ADP-ribose to the acceptor protein occurs endogenously.

Hormone receptors. 7. Characteristics of insulin receptors in a new line of cloned neonatal rat hepatocytes.

1. A new line of cloned, differentiated rat hepatocytes (RL-PR-C) was evaluated for its usefulness as an in vitro system for studying the regulation of the insulin receptor. 2. Insulin rapidly reversibly and specifically bound to RL-PR-C hepatocytes. Binding of tracer 125I-labeled insulin, which was competitively inhibited by native insulin as well as by proinsulin and analogs of insulin and proinsulin in proportion to their biological activity, was not influenced by glucagon, corticotropin, or human growth hormone. Anti-insulin receptor serum from a patient with Acanthosis Nigricans Type B competed with 125I-labeled insulin for binding to cell surface sites. 3. Trypsinization destroyed insulin binding sites, but these were restored by incubation under growth conditions; a 75% restoration of binding sites was achieved by one cell population doubling. 4. RL-PR-C hepatocytes responded to insulin binding by an increase in glycogen synthesis from glucose. The insulin effect was maximal at 85 nM, but was detectable at lower, more physiological, concentrations. 5. Chronic exposure (for at least 3h) of hepatocytes to insulin (10(-10)--(10(-8) M) reduced by up to 60% the number of binding sites for insulin (down-regulation). Down-regulation was prevented by cycloheximide at concentration (10 micron) sufficient to inhibit markedly protein synthesis from tracer isoleucine. Recovery from down-regulation induced by native insulin at 10(-7 M or lower concentrations was complete by 18 h under growth conditions. 6. Although RL-PR-C hepatocytes spontaneously transform after about 90 population doublings, no significant differences between normal and transformed cells were observed in insulin binding characteristics and in interaction of cells with anti-insulin receptor serum. However, transformed cells exhibited a substantially reduced (maximum of 20%) down-regulation response to insulin. 7. RL-PR-C rat hepatocytes appear, for these reasons, to be a useful model system for studying the regulation of the insulin receptor.

Intraperitoneal lymphokine-activated killer-cell and interleukin-2 therapy for malignancies limited to the peritoneal cavity.

Autologous lymphokine-activated killer (LAK) cells and recombinant human interleukin-2 (rIL-2) were administered intraperitoneally (IP) to 24 patients with malignancies limited to the peritoneal space. Ten patients had ovarian cancer, 12 had colorectal cancer, and one patient each had endometrial carcinoma and primary small-bowel adenocarcinoma. All ovarian cancer patients, three of twelve colorectal cancer patients, and one patient with endometrial carcinoma had received prior therapy. Patients received IL-2 100,000 U/kg every 8 hours intravenously (IV) for 3 days, and 2 days later underwent daily leukapheresis for 5 days. LAK cells were generated in vitro by incubating the peripheral blood mononuclear cells in IL-2 for 7 days and were then administered IP daily for 5 days through a Tenckhoff catheter (Davol, Inc, Cranston, RI) together with IL-2 25,000 U/kg IP every 8 hours. All but one patient completed at least one cycle of therapy. Toxic side effects included minor to moderate hypotension, fever, chills, rash, nausea, vomiting, abdominal pain and distension, diarrhea, oliguria, fluid retention, thrombocytopenia, and minor elevations of liver function tests; all of these rapidly improved after discontinuation of IL-2. One patient had a grand mal seizure, and one suffered a colonic perforation; these were felt to be treatment-related. IP fibrosis developed in 14 patients and limited repeated cyclic administration of this therapy in five patients. Two of 10 (20%) ovarian cancer patients and five of 12 (42%) colorectal cancer patients had laparoscopy- or laparotomy-documented partial responses. We conclude that LAK cells and rIL-2 can be administered IP to cancer patients, resulting in moderate to severe short-term toxicity and modest therapeutic efficacy. Further investigation of this form of adoptive immunotherapy modified to address the problem of IP fibrosis and with lower IP IL-2 doses is justified by these initial results.

A menstrual cycle pattern for cytokine levels exists in HIV-positive women: implication for HIV vaginal and plasma shedding.

OBJECTIVES: To evaluate the effect of the menstrual cycle in HIV-positive women on plasma and genital cytokine levels, interrelationships between vaginal and plasma cytokines, CD4 and CD8 T cell fluctuations, and genital and plasma viral loads. METHODS: Plasma and cervicovaginal lavage specimens were collected from 55 HIV-positive women with CD4 cell counts < 350 cells/microl during phases of the menstrual cycle. Samples were assayed for IL-1beta, IL-6, IL-4, IL-8, IL-10, TGFbeta, TNFalpha, INFgamma, MIP1alpha, MIP1beta, RANTES, and TNFR-II using enzyme-linked immunosorbent assays. CD4 and CD8 T cell expression was evaluated by flow cytometry. Repeated measures regression models were used to assess the effect of the menstrual cycle on cytokines and viral load. Multivariate repeated regression models were used to assess the correlation among selected cytokines and between selected cytokines and HIV viral load. RESULTS: Vaginal IL-1beta, IL-4, IL-6, IL-8, IL-10, MIP1beta, RANTES, TGFbeta, and TNFR-II were significantly elevated during menses but were not altered during other phases. Plasma cytokine levels were not altered during the menstrual cycle. A positive Candida culture increased vaginal IL-8 during menses, whereas vaginal discharge was associated with a reduction in vaginal IL-4, IL-10, and RANTES. CD4 and CD8 cell numbers did not vary with the menstrual cycle. Vaginal cytokine levels correlated only with vaginal viral load, in a sampling method-dependent manner. CONCLUSION: We provide evidence of elevated vaginal cytokine levels during menses, which appear to regulate vaginal and not plasma HIV shedding, suggesting that a menstrual cycle pattern exists for cytokine production in HIV-positive women impacting vaginal shedding of HIV.

Effect of menstrual cycle on HIV-1 levels in the peripheral blood and genital tract. WHS 001 Study Team.

OBJECTIVE: To assess the variation in HIV-1 over the menstrual cycle, including RNA levels in the female genital tract, plasma HIV-1-RNA levels, CD4 cell counts, and culturable virus. DESIGN: A prospective analysis of 55 HIV-1-infected women. METHODS: Blood and genital tract specimens were collected weekly over 8 weeks, spanning two complete menstrual cycles. Applying repeated-measures models that used menses as the reference level, the variation in viral RNA levels was compared in endocervical canal fluid and cells (collected by Sno-strips and cytobrush, respectively) and ectocervicovaginal lavage (CVL) fluid. Repeated-measures models were also used to assess the variation in plasma CD4 cell counts and viral load. RESULTS: Shedding patterns differed among the three sampling methods, independent of genital tract co-infections. Genital tract HIV-1-RNA levels from CVL fluid and endocervical canal cytobrush specimens were highest during menses and lowest immediately thereafter (P = 0.001 and P = 0.04). The HIV-1-RNA level in endocervical canal fluid was highest in the week preceding menses (P = 0.003). The menstrual cycle had no effect on blood levels of RNA (P = 0.62), culturable virus (P = 0.34), or CD4 cell counts (P = 0.55). HIV-1-RNA levels were higher in endocervical canal fluid than in peripheral blood plasma during the late luteal phase (P = 0.03). CONCLUSION: HIV-1-RNA levels vary with the menstrual cycle in the female genital tract but not the blood compartment. HIV-1-RNA levels are higher in endocervical canal fluid than in blood plasma. These findings may have important implications for sex-specific pathogenesis, heterosexual transmission, and contraceptive hormone interventions in HIV-1-infected women.

Decreased potency of glucagon on transformed-induced MDCK cells does not reflect an alteration of adenylate cyclase components.

The selective loss of glucagon sensitivity of transformed MDCK cells can be restored by differentiation inducers, a process which requires RNA and protein synthesis and glycosylation. Although the glucagon dose-response curve of normal MDCK cells resembled that of liver and kidney (Kact = 10 nM), the transformed-induced cells were 10-fold less sensitive to the hormone [activation constant (Kact) = 100 nM]. Additionally, the stimulation of cAMP synthesis by a glucagon fragment (glucagon) in transformed-induced cells was greatly reduced compared to normal cells. The adenylate cyclase regulatory components of transformed-induced MDCK cell membranes seemed unaltered compared to the parental line. Both contained equivalent amounts of cholera and pertussis toxin substrates, and soluble extracts were equally capable of reconstituting isoproterenol responsiveness of S49 cyc- membranes. However, membrane fusion studies demonstrated that the glucagon sensitivity of transformed-induced membranes could not be reconstituted with heterologous membranes. When donor transformed-induced membranes (with inactivated adenylate cyclase) were fused with acceptor HeLa membranes (normally unresponsive to glucagon and prostaglandin E), such hybrids were unresponsive to glucagon, although responsiveness to prostaglandin E was evident. Parallel hybrids with normal MDCK membranes were responsive to both glucagon and prostaglandin E. This difference could not be explained by an inhibitory effect of transformed-induced membranes on receptor-adenylate cyclase coupling under the fusion conditions: the ability of these membranes to serve as an acceptor for the reconstitution of vasoactive intestinal peptide responsiveness was identical to that of normal MDCK cells. The data suggest that the glucagon sensitivity induced in transformed MDCK cells differs significantly from that of the parental line. However, these differences cannot be explained by alterations of transformed-induced membrane components relevant to the coupling of hormone receptors to adenylate cyclase.

Decreased adenylate cyclase responsiveness of transformed cells correlates with the presence of a viral transforming protein.

The adenylate cyclase responsiveness of transformed fibroblastic and epithelial cell lines to forskolin, fluoride, guanine nucleotides and cholera toxin was reduced compared to their parental counterparts. This phenomenon was observed in lines transformed by either RNA or DNA tumor viruses, and in the case of polyoma virus, coincided with the expression of middle T antigen. The data suggest that decreased responsiveness of adenylate cyclase to non-hormone activators is a general consequence of viral transformation and may be related to viral regulation of protein kinase activity.

The impact of the ovulatory cycle on cytokine production: evaluation of systemic, cervicovaginal, and salivary compartments.

To understand the impact of the menstrual cycle on immunologic parameters, we measured the level of cytokines and chemokines from plasma, cervicovaginal lavage (CVL), and saliva samples of 6 premenopausal women during the follicular and luteal phases of the ovulatory cycle. We demonstrate that the level of plasma interleukin-8 (IL-8) was 4-fold higher during the follicular phase than the luteal phase (p = 0.004), whereas plasma IL-1beta, IL-4, IL-6, IL-10, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), and TNF receptor II (TNFR II) were not altered during the ovulatory cycle. In the vaginal compartment, as measured from CVL samples, the levels of IL-6 and IL-1beta were both 5-fold higher in the follicular than the luteal phase (p = 0.0002 and 0.03, respectively). Salivary cytokine and chemokine samples were similar when measured during the luteal and the follicular phases. Additional analysis of lymphocyte subsets for phenotypic and functional markers indicated that they were not influenced by the ovulatory cycle. Collectively, these data suggest that IL-6, IL-8, and IL-1beta are differentially regulated during the ovulatory cycle.

Inhibition of adenylate cyclase by IL 2 in human T lymphocytes is mediated by protein kinase C.

Interleukin 2 (IL 2) inhibited basal as well as PGE2, isoproterenol and forskolin stimulated cAMP production in human T lymphocytes. Although the stimulation of adenylate cyclase by activators of the enzyme was evident in lymphocyte membrane preparations, the inhibitory effect of IL 2 was observed only if cells were pretreated with IL 2 and the membranes activated with Ca++ and ATP. Additionally, when purified protein kinase C was reconstituted into untreated membranes and activated with Ca++ and ATP, both receptor and non-receptor stimulated adenylate cyclase was inhibited. These results suggest that the inhibition of adenylate cyclase in human T lymphocytes by IL 2 is mediated by protein kinase C.

Potentiation of lymphokine-activated killer cell differentiation and lymphocyte proliferation by stimulation of protein kinase C or inhibition of adenylate cyclase.

Interleukin 2 (IL-2) stimulated the differentiation of human peripheral blood leukocytes into lymphokine-activated killer cells, as well as DNA synthesis of human T lymphocytes. Both effects of IL-2 could be inhibited by prostaglandin E2, a potent stimulator of adenylate cyclase; however, the inhibitory effect of prostaglandin E2 could be overcome by increased concentrations of IL-2. The opposite effects of IL-2 and prostaglandin E2 were paralleled by their respective abilities to inhibit and stimulate cAMP production in intact cells. Other agents, which inhibit adenylate cyclase directly (somatostatin, beta-endorphin, UK 14.3041) or indirectly by activation of protein kinase C (phenylephrine), could stimulate both differentiation and proliferation. None of these agents alone or in combination were as effective as maximal concentrations of IL-2. However, all agents potentiated differentiation and proliferation induced by submaximal and maximal concentrations of IL-2. Additionally, combinations of agents which stimulated protein kinase C with those that inhibited adenylate cyclase were additive in the potentiation of IL-2-induced differentiation. Neither inhibition nor potentiation of IL-2-induced lymphokine-activated killer cell differentiation was accompanied by changes in Tac expression or gamma-interferon production. The data indicate that the stimulation of lymphokine-activated killer cell differentiation and lymphocyte proliferation in human cells share a common initial biochemical signal. Although the inhibition of adenylate cyclase is not sufficient to maximally stimulate either process and cannot bypass the requirement for IL-2, modulation of this enzyme complex, positively or negatively, can regulate the ultimate physiologic response to IL-2.