Enhancement of anti-cancer activity of cytotoxic chemotherapy with protection of normal tissues by inhibition of P.G. synthesis

Mononuclear metal complexes with Piroxicam: Synthesis, structure and biological activity

Piroxicam (=Hpir) is a non-steroidal anti-inflammatory and an anti-arthritic drug. VO(2+), Mn(2+), Fe(3+), MoO(2)(2+) and UO(2)(2+) complexes with deprotonated piroxicam have been prepared and characterized with the use of infrared, UV-Vis, nuclear magnetic resonance and electron paramagnetic resonance spectroscopies. The experimental data suggest that piroxicam acts as a deprotonated bidentate ligand in all complexes and is coordinated to the metal ion through the pyridine nitrogen and the amide oxygen. Molecular mechanics calculations in the gas state have been performed in order to propose a model for the Fe(3+), VO(2+) and MoO(2)(2+) complexes. Potential anticancer cytostatic and cytotoxic effects of piroxicam complexes with VO(2+), Mn(2+) and MoO(2)(2+) on human promyelocytic leukemia HL-60 cells have been investigated. Among all complexes, only VO(pir)(2)(H(2)O) clearly induces apoptosis after 24-h incubation, whereas piroxicam induces apoptosis after 57-h incubation.

Enhancement of chemotherapeutic drug toxicity to human tumour cells in vitro by a subset of non-steroidal anti-inflammatory drugs (NSAIDs)

The effect on cytotoxicity of combining a range of clinically important non-steroidal anti-inflammatory drugs (NSAIDs) with a variety of chemotherapeutic drugs was examined in the human lung cancer cell lines DLKP, A549, COR L23P and COR L23R and in a human leukaemia line HL60/ADR. A specific group of NSAIDs (indomethacin, sulindac, tolmetin, acemetacin, zomepirac and mefenamic acid) all at non-toxic levels, significantly increased the cytotoxicity of the anthracyclines (doxorubicin, daunorubicin and epirubicin), as well as teniposide, VP-16 and vincristine, but not the other vinca alkaloids vinblastine and vinorelbine. A substantial number of other anticancer drugs, including methotrexate, 5-fluorouracil, cytarabine, hydroxyurea, chlorambucil, cyclophosphamide, cisplatin, carboplatin, mitoxantrone, actinomycin D, bleomycin, paclitaxel and camptothecin, were also tested, but displayed no synergy in combination with the NSAIDs. The synergistic effect was concentration dependent. The effect appears to be independent of the cyclo-oxygenase inhibitory ability of the NSAIDs, as (i) the synergistic combination could not be reversed by the addition of prostaglandins D2 or E2; (ii) sulindac sulphone, a metabolite of sulindac that does not inhibit the cyclooxygenase enzyme, was positive in the combination assay: and (iii) many NSAIDs known to be cyclo-oxygenase inhibitors, e.g. meclofenamic acid, diclofenac, naproxen, fenoprofen, phenylbutazone, flufenamic acid, flurbiprofen, ibuprofen and ketoprofen, were inactive in the combination assay. The enhancement of cytotoxicity was observed in a range of drug sensitive tumour cell lines, but did not occur in P-170-overexpressing multidrug resistant cell lines. However, in the HL60/ADR and COR L23R cell lines, in which multidrug resistance is due to overexpression of the multidrug resistance-associated protein MRP, a significant increase in cytotoxicity was observed in the presence of the active NSAIDs. Subsequent Western blot analysis of the drug sensitive parental cell lines, DLKP and A549, revealed that they also expressed MRP and reverse-transcription-polymerase chain reaction studies demonstrated that mRNA for MRP was present in both cell lines. It was found that the positive NSAIDs were among the more potent inhibitors of [3H]-LTC4 transport into inside-out plasma membrane vesicles prepared from MRP-expressing cells, of doxorubicin efflux from preloaded cells and of glutathione-S-transferase activity. The NSAIDs did not enhance cellular sensitivity to radiation. The combination of specific NSAIDs with anticancer drugs reported here may have potential clinical applications, especially in the circumvention of MRP-mediated multidrug resistance.

On radiation damage to normal tissues and its treatment. II. Anti-inflammatory drugs

In addition to transiently inhibiting cell cycle progression and sterilizing those cells capable of proliferation, irradiation disturbs the homeostasis effected by endogenous mediators of intercellular communication (humoral component of tissue response to radiation). Changes in the mediator levels may modulate radiation effects either by assisting a return to normality (e.g., through a rise in H-type cell lineage-specific growth factors) or by aggravating the damage. The latter mode is illustrated with reports on changes in eicosanoid levels after irradiation and on results of empirical treatment of radiation injuries with anti-inflammatory drugs. Prodromal, acute and chronic effects of radiation are accompanied by excessive production of eicosanoids (prostaglandins, prostacyclin, thromboxanes and leukotrienes). These endogenous mediators of inflammatory reactions may be responsible for the vasodilatation, vasoconstriction, increased microvascular permeability, thrombosis and chemotaxis observed after radiation exposure. Glucocorticoids inhibit eicosanoid synthesis primarily by interfering with phospholipase A2 whilst non-steroidal anti-inflammatory drugs prevent prostaglandin/thromboxane synthesis by inhibiting cyclooxygenase. When administered after irradiation on empirical grounds, drugs belonging to both groups tend to attenuate a range of prodromal, acute and chronic effects of radiation in man and animals. Taken together, these two sets of observations are highly suggestive of a contribution of humoral factors to the adverse responses of normal tissues and organs to radiation. A full account of radiation damage should therefore consist of complementary descriptions of cellular and humoral events. Further studies on anti-inflammatory drug treatment of radiation damage to normal organs are justified and desirable.

Acetylsalicylic acid (ASA) protects the prostaglandin-cAMP-system of human hypernephroma cells against irradiation-induced alterations

There is abundant evidence that inhibitors of prostaglandin (PG) biosynthesis might increase the radioresponse of certain tumour cells. This study investigated specific PG binding sites, eicosanoid production as well as intracellular cAMP levels in cultured human hypernephroma cells derived from 11 patients upon nephrectomy. Scatchard analyses of the binding data revealed specific PGE1-, PGE2- as well as PGI2-binding sites (PGE1: Bmax = 755 +/- 206 fmol mg-1 protein, Kd = 3.7 +/- 2.7 nM PGE2: Bmax = 494 +/- 221 fmol mg-1 protein, Kd = 4.2 +/- 2.5 nM; PGI2: Bmax = 693 +/- 164 fmol mg-1 protein, Kd = 6.0 +/- 4.5 nM). Significant (P < 0.01) increase in PG binding sites expressed on human hypernephroma cells (PGE1: Bmax = 1084 +/- 303 fmol mg-1 protein, Kd = 2.8 +/- 1.3 nM; PGE2: Bmax = 663 +/- 309 fmol mg-1 protein, Kd = 2.2 +/- 1.5 nM; PGI2: Bmax = 1021 +/- 391 fmol/protein, Kd = 4.2 +/- 3.6 nM) and inhibition of PG biosynthesis (TXB2: -82.5%, PGE2: -87.5%. PGD2: -80.6%, PGF2: -81.3%) were found after acetylsalicylic acid (ASA)-treatment (0.5 mg 10(-6) cells for 24 h). Following irradiation (60Co, 1.0 Gy/min-1 over 10(min), PG binding sites (PGE1: Bmax = 266 +/- 153 fmol mg-1 protein, Kd = 5.0 +/- 5.0 nM; PGE2: Bmax = 148 +/- 66 fmol mg-1 protein, Kd = 4.7 +/- 3.6 nM; PGI2: Bmax = 325 +/- 194 fmol mg-1 protein, Kd = 6.8 +/- 7.1 nM) were significantly (P < 0.01) diminished. However, irradiation had no significant effect on PG binding sites in ASA-pretreated cells (PGE1: Bmax = 699 +/- 240 fmol mg-1 protein, Kd = 3.5 +/- 1.8 nM; iloprost: Bmax = 766 +/- 452 fmol mg-1 protein, Kd = 3.2 +/- 2.2 nM). Although there was no significant difference in the basal values for cAMP between control and ASA-treated group cells, the PG-induced cAMP-production was less pronounced in the control group. Taken together, the findings suggest that ASA may modify the radioresponse of cultured human hypernephroma cells by preventing the decrease of PG binding sites induced by irradiation.

Influence of inhibitors of eicosanoid metabolism on proliferation of rat hepatoma cells and on tumor-host interaction

The influence of eicosanoids on the proliferation of hepatoma (HTC) cells was studied in culture and in tumor-bearing rats. The cells in culture demonstrated a capacity to metabolize arachidonic acid to eicosanoids including thomboxane B2 and the prostaglandins E2 and F2 alpha a. An effect of these eicosanoids on cell proliferation was suggested by the decreased cell division seen with an inhibitor of cyclooxygenase, flurbiprofen. A biphasic effect on the proliferation of HTC cells was observed with increasing concentrations of prostaglandin F2 alpha. These studies were extended to tumor-bearing rats where inhibitory effects on the early stages of tumor growth were seen with flurbiprofen. Bleeding times were decreased in tumor-bearing rats but were restored to control values by treatment with flurbiprofen and an inhibitor of thromboxane synthetase, OKY 046. These drugs and a thromboxane/endoperoxide receptor antagonist, SQ 29, 548, were not observed to have statistically significant effects on isotope-labeled water distribution but they had substantial effects on the maintenance of body weight by tumor-bearing rats. The data suggested that the cachexia of tumor-bearing animals may be mediated at least in part by the action of eicosanoids.

Prostaglandin synthesis by squamous carcinoma cells of head and neck, and its inhibition by non-steroidal anti-inflammatory drugs

The purpose of this study was to determine the nature and amounts of prostaglandins (PGs) produced by squamous carcinoma cells (SCC) and the sensitivity of these cells to non-steroidal anti-inflammatory drugs. SCC of four lines of the tongue and one line of facial epidermis of humans were incubated in phosphate buffer solution with 14C-arachidonic acid (AA). Radioactive metabolites in aqueous methanol were chromatographed on Sep-Pack C18 cartridges, separated and quantitated by means of TLC, autoradiography, and liquid scintillation counting. The results showed that cyclooxygenase products, PGs, were the major products formed by all cell lines, and PGE2 was predominant among the PGs detected. Two radioactive bands corresponding to PGF2 alpha and three unseparated standards of PGA2, 15-keto-PGE2, and 13,14-dihydro-15-keto-PGE2 were detected in lesser amounts. Very small amounts of the lipoxygenase products 12- and 15-HETE were found. The concentrations of indomethacin, ibuprofen and aspirin required to inhibit 50% of PGE2 synthesis (IC50) by SCC lines were .008-.080, .080-6.4 and 32-88 microM, respectively.

Studies on the mechanism by which indomethacin increases the anticancer effect of methotrexate

The effect of indomethacin on the response of the NC carcinoma to methotrexate has been examined in vivo and in vitro. Survival was prolonged in mice treated with indomethacin 1.25 mg kg-1 twice daily plus methotrexate 4 mg kg-1 daily, compared to mice given either drug alone or controls. Indomethacin 1 microgram ml-1 increased the killing of cultured NC cells by methotrexate. This was not due to displacement of methotrexate from binding sites on the serum proteins. Nor was it due (entirely) to inhibition of prostaglandin synthesis, since flurbiprofen did not mimic the effect. Inhibition of cyclic AMP phosphodiesterase seems unlikely to explain the effect of indomethacin since theophylline had little or no effect on NC cell killing by methotrexate. Indomethacin 1 microgram ml-1 increased the accumulation of tritium in NC cells incubated with [3H]-methotrexate. In contrast, with normal epithelial cells from human embryonic intestine, indomethacin 1 microgram ml-1 did not alter the cytotoxicity of methotrexate or the accumulation of tritium during incubation with [3H]-methotrexate. The beneficial interaction between indomethacin and methotrexate may have therapeutic potential in man.

Flurbiprofen for the treatment of bone pain in patients with metastatic breast cancer

Two investigators enrolled 26 women with metastatic breast carcinoma in a six-week, double-blind, placebo-controlled, crossover study of flurbiprofen (Ansaid, Upjohn) and placebo. The study was designed to determine the efficacy of flurbiprofen in reducing bone pain due to metastatic breast cancer. Pain score, overall performance, and concomitant use of narcotics were evaluated. The overall mean differences in pain scores between flurbiprofen and placebo showed better control of pain during treatment with flurbiprofen. None of these differences approached statistical significance. Evaluation of overall performance status reached statistical significance in one investigator's group. Three out of four patients reported decreased consumption of acetaminophen/aspirin plus codeine combinations while receiving flurbiprofen.

The modulating effects of flurbiprofen on adriamycin plus vincristine or vindesine in the treatment of advanced breast cancer

To assess the modulating effects of a non-steroidal anti-inflammatory drug on chemotherapeutic agents, 183 patients with advanced breast cancer have been treated in a randomised study with flurbiprofen or placebo and adriamycin plus a vinca alkaloid. To assess the efficacy of the new vinca alkaloid, vindesine, in breast cancer, patients were further randomised to receive vindesine or vincristine. The overall response rate in evaluable patients was 57%, and the median duration of response in the different treatment groups varied from 6 to 10 months. Response rates and toxicity in vindesine- and vincristine-treated patients were similar, although with vindesine neurotoxicity was slightly lower. Flurbiprofen did not improve the response rate or reduce the toxicity of adriamycin plus vinca alkaloid.

Rationale for a novel immunotherapy of cancer with allogeneic lymphocyte infusion

A simple method of cancer immunotherapy has been developed which achieves marked objective response in 20-30% of patients with disseminated disease. Each course consists of a low dose of chemotherapy followed two days later by intravenous infusion of allogeneic lymphocytes. Courses are repeated on a monthly basis as needed. The function of the chemotherapy--too mild to significantly influence tumor growth directly--appears to be depletion of suppressor T cells, which sensitizes the patient to the immunostimulant action ("allogeneic effect") of the subsequently infused lymphocytes. The rationale for this method is discussed in the context of a review of past attempts at lymphocyte immunotherapy. We are now attempting to improve response rates by combatting anergy with nutritional immunopotentiators, and by preventing prostaglandin-mediated or -dependent immunosuppression with prostaglandin synthetase inhibition. By understanding and counteracting the various specific and general means by which a growing tumor induces host tolerance, it should prove possible to achieve immune-mediated tumor regression in a high proportion of patients. Best results may be seen when allogeneic lymphocyte therapy is initiated at an earlier stage of the disease, and is used in conjunction with surgery, radiotherapy, short-course intensive chemotherapy, or hyperthermia-based methods.

Response of human adenocarcinoma to chemotherapy: as sole agents and in combination with sodium ibuprofen

The sensitivity of 12 human tumors to various chemotherapeutic agents was measured in the 6-day subrenal capsule xenograft assay. All of the tumors were adenocarcinomas: 9 ovarian, 2 colon, and one endometrial. Doxorubicin, cisplatin, melphalan, 5- fluorouracil , methotrexate, and vinblastine sulfate were tested for antineoplastic activity on all tumors. In addition, a prostaglandin synthetase inhibitor, sodium ibuprofen, was assayed for cytostatic activity and for the ability to enhance the cytotoxic activity of melphalan and vinblastine sulfate. The response of the tumors to the cytotoxic agents were variable, but 5 of the 12 tumors showed a significant reduction of growth when the animals were treated with sodium ibuprofen alone. The addition of ibuprofen to the chemotherapeutic agents did not significantly alter the therapeutic activity of melphalan, but decreased the effectiveness of vinblastine in one case. When ibuprofen was given in combination with a cytotoxic drug, the primary cytoreductive effect was that of the cytotoxic agent.

Failure of short-term treatment with flurbiprofen to enhance the therapeutic effect of cyclophosphamide against rodent sarcomas and a leukaemia

Animals bearing metastatic fibrosarcomas were treated with cyclophosphamide (CY) alone or in combination with flurbiprofen (FP), an inhibitor of prostaglandin synthesis. FP did not affect local growth of fibrosarcomas, and the incidence of distant metastases after resection of the "primary" implants was comparable in treated and control groups. Treatment with CY retarded growth of the fibrosarcomas and reduced the proportion of animals which succumbed to metastases, but this was not altered significantly by additional treatment with FP. FP did not affect the survival of rats bearing a lymphoid leukaemia. The lifespan of animals treated with CY was increased significantly, but the concomitant administration of FP did not enhance this effect.

Increased survival of cancer-bearing mice treated with inhibitors of prostaglandin synthesis alone or with chemotherapy

In mice with a transplantable mammary carcinoma, treatment with the prostaglandin-synthesis inhibitors flurbiprofen or indomethacin produced various beneficial effects. Survival time after excision of the transplanted tumour was increase, particularly when the drugs were given with the chemotherapeutic agents methrotrexate and melphalan, and there were more disease-free survivors. The combined treatment with flurbiprofen also gave less tumour recurrence at the excision site. Flurbiprofen did not seem to alter the bioavailability of the chemotherapeutic agents.

Effect of chlorambucil and indomethacin on growth and prostaglandin levels in sensitive and resistant Walker carcinoma

An analysis of the effect of combinations of chlorambucil and indomethacin, or chlorambucil and prostaglandin E2 (PGE2) on the growth of alkylating agent sensitive and resistant Walker carcinoma in vitro has been made by the isobologram approach. Indomethacin alone acts as a growth inhibitor of the Walker carcinoma. High concentrations of indomethacin (5 microgram/ml) act to inhibit the growth of the resistant line sub-additively with chlorambucil, whereas low concentrations act additively. For the sensitive line indomethacin acts either additively or supra-additively with chlorambucil at all concentrations employed. Both indomethacin and low concentrations of chlorambucil alone inhibit PGE2 secretion into the culture medium of both cell lines and an enhanced inhibition is seen with the combination. PGE2 itself acts as a growth inhibitor of both cell lines, although it causes greater growth inhibition of chlorambucil resistant Walker carcinoma (LD50 1.8 microgram/ml) than of the sensitive line. This correlates with a greater PGE2 secretion capacity by the resistant cell line (40 pg PGE2/ml medium/10(5) cells for the resistant tumour and 17 pg PGE2/ml medium/10(5) cells for the sensitive tumour). Combinations of PGE2 with chlorambucil inhibit growth either additively or sub-additively. It seems unlikely that inhibition of PGE2 secretion is responsible for the interactive effects of chlorambucil and indomethacin, since growth inhibition produced by the combination is not reversed by PGE2 at any of the concentrations employed. Possible mechanisms of the interactive effects are discussed.

Macrophages and neoplasms: new insights and their implication in tumor immunobiology

In this review, I have attempted to draw together some recent findings of current importance in tumor-macrophage interactions. The widespread distribution of macrophages through the body, the ease of monocyte mobilization to inflammatory sites, the exquisite synthetic machinery of the macrophage and its potent antitumor activity, when this can be evoked by nonspecific means, imply a critical role for cells of this lineage in regulation and control of the neoplastic state. These new insights into the immunobiology of the macrophage revive our hopes both for a keener understanding of the complexity existing between the host and its neoplasm and for the development of successful therapies based on scientifically proven rationales.

Decrease in aspirin-induced gastric mucosal damage in rats by oral administration of the cytotoxic drugs melphalan and methotrexate

Gastric mucosal damage by aspirin and chemotherapeutic drugs was studied in Wistar rats. Aspirin 60 mg given by stomach tube caused substantial gastric mucosal damage as judged by visual examination of the stomachs removed four hours later. Melphalan and methotrexate given daily for four days had no significant macroscopic effect on the gastric mucosa, but reduced the damage caused by aspirin. This protective effect my involve a stimulation of prostaglandin synthesis by the stomach, increased mucus secretion, and/or inhibition of acid secretion.

Review: prostaglandins and cancer

This paper reviews work on the role of prostaglandins in cancer. A substantial body of evidence demonstrates elevated amounts of E series of prostaglandins in human and experimental tumors. Blockade of prostaglandin synthesis in vitro or in vivo results in inhibition of tumor growth. Involvement of prostaglandins is implicated in the actions of tumor promoters like phorbol and polycyclic aromatic hydrocarbon carcinogens. Symptoms like hypercalcemia, osteolysis and tumor metastasis are discussed where disordered synthesis and/or action of prostaglandins and related substances might have a role in the altered metabolism associated with neoplasia.

Use of non-steroidal anti-inflammatory drugs in the treatment of pain in cancer

1 Prostaglandins may precipitate or exacerbate pain and they may be produced by several tumours. 2 Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandin synthesis and may also inhibit bone metastases and enhance immune responses. 3 NSAIDs alone or in association with narcotics or psychotropics may not only afford the best pain relief in neoplastic disease, but also modify the progress of the tumour. 4 The effect of NSAIDs on the gastrointestinal tract is generally adverse.

Breast cancer and prostaglandins: a new approach to treatment

The effect of the non-steroidal inhibitor of prostaglandin synthesis, flurbiprofen, has been studied on a transplanted mouse mammary tumour of spontaneous origin. Daily administration of 2.5 mg/kg flurbiprofen signficantly reduced the growth of this NC adenocarcinoma transplanted subcutaneously into the right flank of WHT/Ht mice. Histological examination showed that primary tumours excised at 3 weeks from treated mice tended to have a more prominent lymphocytic infiltration. There was a non-significant tendency for mice treated with flurbiprofen alone to survive longer after tumour excision and to develop less local metastases, although scar recurrences seemed unaffected. The effect of adjuvant chemotherapy and local radiotherapy on local metastases and survival time tended to be greater when flurbiprofen was also given. This work supports and extends the basis for prospective clinical trials to evaluate the role of prostaglandins in human cancer and the value of prostaglandin synthesis inhibitors in cancer therapy.