N-Hydroxyformamide LpxC inhibitors, their in vivo efficacy in a mouse Escherichia coli infection model, and their safety in a rat hemodynamic assay.

UDP-3-O-(R-3-hydroxyacyl)-N-acetylglucosamine deacetylase (LpxC), the zinc metalloenzyme catalyzing the first committed step of lipid A biosynthesis in Gram-negative bacteria, has been a target for antibacterial drug discovery for many years. All inhibitor chemotypes reaching an advanced preclinical stage and clinical phase 1 have contained terminal hydroxamic acid, and none have been successfully advanced due, in part, to safety concerns, including hemodynamic effects. We hypothesized that the safety of LpxC inhibitors could be improved by replacing the terminal hydroxamic acid with a different zinc-binding group. After choosing an N-hydroxyformamide zinc-binding group, we investigated the structure-activity relationship of each part of the inhibitor scaffold with respect to Pseudomonas aeruginosa and Escherichia coli LpxC binding affinity, in vitro antibacterial potency and pharmacological properties. We identified a novel, potency-enhancing hydrophobic binding interaction for an LpxC inhibitor. We demonstrated in vivo efficacy of one compound in a neutropenic mouse E. coli infection model. Another compound was tested in a rat hemodynamic assay and was found to have a hypotensive effect. This result demonstrated that replacing the terminal hydroxamic acid with a different zinc-binding group was insufficient to avoid this previously recognized safety issue with LpxC inhibitors.

2-Pyridineformamide N(4)-ring incorporated thiosemicarbazones inhibit MCF-7 cells by inhibiting JNK pathway.

In an effort to develop a more potent anticancer therapeutic agent, a series of 2-pyridineformamide thiosemicarbazones (R = H, 4-CH3, 5-F, 6-CH3 and ) have been synthesized and evaluated for their anti-cancer activities against the cancer cells MCF-7 (breast cancer cell line), A-431 and A375 (epidermoid carcinoma cell line), and HeLa (cervical cancer cell line) using MTT assay. All these 2-pyridineformamide thiosemicarbazones exhibited anti-proliferative activities towards these cell lines. 5FAmPyrr possess most profound effects against MCF-7 cells with IC50 of 0.9 µM. In flow cytometry using Propidium Iodide, 5FAmPyrr was found to induce cell death significantly in a dose dependent manner (100 nM-3 µM) and inhibited colony formation of MCF-7 cells. This compound induced pro-apoptotic protein Bax and inhibited anti apoptotic protein Bcl-2 as well as both c-Jun and Jun N-terminal kinase (abbreviated as JNK) in concentration dependent manner. Further pro-caspase 3 and PARP were inhibited by 5FAmPyrr at concentration of 3 µM. The results suggest that 5FAmPyrr exhibit anticancer potency and induced cell death by inhibiting MAPK signaling and inducing intrinsic apoptotic pathway. All these indicate that 2-pyridineformamide thiosemicarbazones could be developed as future therapeutics agents to treat cancer.

Discovery of 2-pyridineformamide thiosemicarbazones as potent antiausterity agents.

Series of 2-pyridineformamide thiosemicarbazones were synthesized. Their preferential cytotoxicity in nutrient deprived medium (NDM) was evaluated using PANC-1 human pancreatic cancer cells by employing an antiausterity strategy. 2-Pyridineformamide thiosemicarbazones induced apoptosis and exhibited preferential cytotoxic activity toward PANC-1 cells in NDM, with potencies in the submicromolar range. These compounds are potential candidates for the development of therapeutics against pancreatic cancer.

Effect of gelatinase inhibition on adipogenesis and adipose tissue development.

1. The potential of the matrix metalloproteinase (MMP) inhibitor ABT-518 to affect pre-adipocyte differentiation in vitro and adipose tissue development in vivo was investigated using mouse models of adipogenesis and obesity. 2. Differentiation of 3T3-F442A pre-adipocytes into mature adipocytes was enhanced in a dose-dependent manner by the addition of ABT-518 (0-100 µmol/L). This was associated with increased expression of the adipogenic markers adipocyte fatty acid-binding protein 2 (AP2), peroxisome proliferator-activated receptor γ and adiponectin. 3. Feeding 5-week-old male wild-type mice with a high-fat diet, with or without ABT-518 (to achieve a dose of 100 mg/kg per day), for 16 weeks resulted in a significant reduction in bodyweight throughout the experimental period. Magnetic resonance spectroscopy revealed that the lipid : water ratio was significantly lower in ABT-518-treated mice. The total weight of isolated subcutaneous or gonadal fat depots did not differ significantly following ABT-518 treatment, but adipocyte and blood vessel size were significantly reduced in the gonadal fat. 4. Administration of ABT-518-2 (100 mg/kg per day for 10 weeks) to 5-week-old male wild-type mice with established obesity maintained on a high-fat diet had no effect on total bodyweight at the end of the experiment, but was associated with reduced blood vessel size in the fat depots. 5. Thus, the MMP inhibitor ABT-518 stimulates differentiation of 3T3-F442A pre-adipocytes in vitro. It mildly reduces bodyweight gain in a murine model of diet-induced obesity, but does not affect established obesity.

Continuous inhibition of 20-HETE synthesis by TS-011 improves neurological and functional outcomes after transient focal cerebral ischemia in rats.

TS-011, a potent and selective inhibitor of 20-HETE synthesis, has been described as providing significant benefits in animal stroke models. However, no studies have investigated changes in brain 20-HETE levels after cerebral ischemia. Also lacking are studies of TS-011 pharmacodynamics with respect to brain 20-HETE levels that may explain the benefits of TS-011 in animal models of ischemic stroke. The present study sought to explore changes in 20-HETE levels in brain tissue, as well as in plasma, after a 90-min episode of transient focal cerebral ischemia. Pharmacodynamics of TS-011 were also examined. Then, we evaluated the long-term effects of TS-011 when administered as in this pharmacodynamics study. The major findings of the present study are as follows: (1) brain 20-HETE levels increased significantly within 7.5h after MCAO; (2) TS-011 at doses of 0.1 and 0.3mg/kg administered at regular 6-h intervals appeared to reduce brain 20-HETE levels continuously; (3) TS-011 when administered as in this pharmacodynamics study improved long-term neurological and functional outcomes. These findings strongly suggest that 20-HETE plays an important role in the development of neurological and functional deficits after focal cerebral ischemia and that TS-011 may provide benefits in patients suffering ischemic stroke.

Enhancement by N-methylformamide of the effect of ionizing radiation on a human colon tumor xenografted in nude mice.

Polar solvents, which induce differentiation in murine and human tumor cells, enhance the effect of ionizing radiation on cultured mouse mammary and human colon cancer cells. To determine whether this enhancement occurs in vivo, DLD-2 human colon carcinoma xenografts in nude mice were treated with combinations of 6 MV photon irradiation, the polar solvent N-methylformamide (NMF), or combinations of the two agents. Nude mice bearing 300-mg s.c. implants of DLD-2 tumors were treated i.p. with 150 mg NMF/kg daily for 19 days. Local tumor irradiations were administered as graded single doses or as fractionated doses, daily for 4 days, following the third NMF injection. The growth-inhibiting effect of the radiation treatment for both single dose and fractionation protocols was enhanced by the polar solvent. NMF alone increased the time required for a doubling of initial tumor volume by 1.7 days, compared to control tumors. Initial tumor volume doubling times compared to untreated controls were increased by 3.6 and 7.6 days by photon doses of 10.0 and 13.75 Gy, respectively, whereas NMF plus 10.0 or 13.75 Gy increased the DLD-2 regrowth delay time by 7.5 or 12.9 days. NMF caused essentially equivalent enhancements, whether split-dose schedules of 2.5 Gy daily for 4 days, and 3.44 Gy daily for 4 days, or single doses of 10.0 and 13.75 Gy were used; therefore, radiation enhancement was not due to effects on sublethal damage repair. The results support the use of NMF, currently in Phase 1-Phase 2 clinical trials, with radiation in the therapy of selected human neoplasms.

Phase I trial of N-methylformamide (NMF, NSC 3051).

N-methylformamide (NMF) is a polar-planar solvent with both cytotoxic and differentiating activity in preclinical models; it also acts as a radiosensitizer. We treated 17 patients with 18 courses of NMF on a schedule of six weekly doses, administered on a rapid intravenous infusion, which were escalated from 875 to 2,000 mg/m2/wk. The predominant toxicity was a dose-related syndrome of fatigue, malaise, nausea, and anorexia, which was reflected by a decrease in performance status (Karnofsky) of greater than or equal to 20% in six of ten patients who received doses greater than or equal to 1,500 mg/m2/wk. Other gastrointestinal toxicities included moderate vomiting and mild diarrhea. Reversible increase of liver enzymes occurred in six of ten patients at doses greater than or equal to 1,500 mg/m2/wk. The maximum tolerated dose on this schedule is 1,500 mg/m2/wk; the dose recommended for phase II studies is 1,125 mg/m2/wk. Future studies of this regimen in a combined modality setting are planned.

N-methylformamide affects spontaneous metastases of 3LL lines and increases natural killer activity of tumor-bearing mice.

The antitumor activity of the polar solvent N-methylformamide (NMF) was evaluated on three lines derived from the Lewis lung carcinoma (3LL), endowed with different metastatic potential. Two administration schedules were tested, these being repeated regimens of NMF (200 mg/kg per dose) for 12 consecutive days, starting 24 h or 6-10 days after tumor implantation (early or late treatment, respectively). The results of the present work can be summarized as follows: (1) NMF regimens did not greatly affect tumor growth behavior of 3LL lines; conversely, they markedly influenced their spontaneous colonizing ability in the lungs, either by delaying early metastatic spread or by reducing the number and size of pulmonary metastases already implanted. (2) A significant increase of NK cell activity during and after early treatment with NMF was observed in the more-metastasizing lines, thus suggesting the possibility of an immunomodulating effect of NMF.

Modification of tumor and normal tissue radioresponse in mice by N-methylformamide.

The effects of the differentiation-inducing agent N-methylformamide (NMF) on the in vivo response of the murine tumor FSA and its pulmonary metastases to ionizing radiation were investigated. In addition, the radioresponse of acutely responding normal tissues was determined in mice receiving systemic NMF. A dosage of 300 mg/kg administered for 8 days had little effect on the FSA tumor growth, yet enhanced the growth inhibitory actions of ionizing radiation with dose enhancement factors ranging from 1.5 to 1.7. Administration of NMF also enhanced the radiation response of FSA micrometastases. The response to irradiation of hematopoietic tissue, jejunum, and testes in mice receiving NMF was also investigated. NMF administered before or before and after radiation enhanced the formation of endogenous spleen colonies, yet did not influence the LD50/30 for radiation. Jejunal crypt cell survival after radiation was slightly increased in mice receiving NMF, but the survival of spermatogonia after radiation was not affected. These data indicate that NMF administration results in an increase in the radiosensitivity of the FSA tumor and its metastases with no concomitant increase in the radiation response of the normal tissue tested. Thus, at least in this model system, a therapeutic gain is achieved through the combination of NMF and ionizing radiation.

Enhancement of the responses of human colon adenocarcinoma cells to X-irradiation and cis-platinum by N-methylformamide (NMF).

The ability of the maturational agent N-methylformamide (NMF) to modify the response of exponentially growing clone A human colon adenocarcinoma cells to x-irradiation, cis-platinum (cis-DDP), or x-irradiation combined with cis-platinum was studied using an in vitro clonogenic assay. When clone A tumor cells were adaptively grown in medium containing 1% NMF (V/V) for 3 passages prior to experiments, a significantly increased sensitivity to x-irradiation as compared to non-NMF treated cells was found. This increased sensitivity was most marked in the low dose region of the survival curve (as indicated by a large increase in the alpha constant in the linear-quadratic equation), and is similar to the increased radiosensitivity observed after treatment of these tumor cells with N,N-dimethylformamide (DMF). Growth in NMF medium also sensitized these cells to the cytotoxic effects of a 1 hr treatment with cis-DDP at 37 degrees C. A dose enhancement factor of about 1.8 was found at the 10% level of survival for the NMF adapted and cis-DDP treated cells as compared to control cells. Clone A cells were treated either immediately prior to or immediately after x-irradiation with a single low dose of cis-DDP (1.5 microgram/ml, 1 hour at 37 degrees C) after adaptation to growth in NMF containing medium, and the modification of the X ray survival curve was compared to cells not exposed to NMF and to NMF-treated cells also treated with cis-DDP. For the non-NMF treated cells, the low dose cis-DDP treatment produced no change in the survival parameters of the X ray survival curve. However, the NMF adapted cells exhibited an additional decrement in cell survival, indicating that the effect of NMF on radiation on cis-DDP cell killing was additive in nature when all 3 agents were combined in this protocol. Also, there was no difference between the sequences of cis-DDP (1 hr, 37 degrees C) + X rays versus X rays + cis-DDP (1 hr, 37 degrees C). These data indicate that combinations of differentiation inducing agents, together with chemotherapeutic agents and X rays, may be a promising avenue of investigation in developing strategies for cancer treatment.

X ray responses of a human colon tumor cell line after exposure to the differentiation-inducing agent N-methylformamide: concentration dependence and reversibility characteristics.

The combination of differentiation-inducing agents with conventional cytotoxic agents has been suggested as a potential cancer therapeutic strategy. In this regard, we have chronically exposed (3 passages) a human colon tumor line (clone A) to varying concentrations (0-170 mM) of N-methylformamide and examined the change in sensitivity to ionizing radiation in vitro. The linear-quadratic formalism of survival was used to characterize the single graded dose survival curves. This equation yields two constants (alpha and beta) relating to cellular inactivation produced by either single events (alpha) or by the combination of two events (beta). As the N-methylformamide concentration increased, the alpha parameter increased while the beta parameter concomitantly decreased, yielding a concentration dependent radiosensitization which was most marked in the low dose region of the survival curve. Upon removal of NMF, the original radiation resistance was regained within 2-3 cell culture doubling times.

The effect of N-methylformamide on radiocurability of murine tumors.

N-Methylformamide (NMF) is a polar solvent with maturational activity, i.e., it induces malignant cells to form more differentiated phenotypes. In addition, it renders tumor cells more sensitive to chemotherapeutic drugs and ionizing radiation. In the present study, NMF failed to augment radiocurability, as measured by the single-dose TCD50 assay, of two murine tumors: an 8-mm fibrosarcoma (FSA) and a 6-mm mammary carcinoma (MCA-K). NMF, at a dose of 300 mg/kg, was given ip daily for several days before and/or after local tumor irradiation.

The antitumour effect and toxicity of cis-platinum and N-methylformamide in combination.

N-Methylformamide (NMF), currently undergoing phase II clinical evaluation for the treatment of cancer, and the established antitumour agent cis-platinum (CDDP) have nonoverlapping toxicities, with the exception of gastrointestinal side effects. The major target organs for the toxicities of the compounds are the liver (NMF) and the kidney (CDDP). Furthermore, NMF is nonleukopenic. In view of this, and of recent evidence that NMF enhances the cytotoxic effect of CDDP in vitro the activity of NMF and CDDP against the M5076 sarcoma implanted in mice was investigated, together with the various toxicities in mice and rats. The antitumour effect of NMF in combination with CDDP was additive, but NMF did not alter the leukopenia produced by CDDP in the tumour-bearing mice. CDDP produced only a minimal increase in the hepatotoxicity of NMF in mice, and NMF did not augment the nephrotoxicity of CDDP in rats (except for a small effect on calcium excretion). The results support suggestions that clinical evaluation of combination chemotherapy with NMF and CDDP is warranted.

The influence of sodium ascorbate, menadione sodium bisulfite or pyridoxal hydrochloride on the toxic and antineoplastic action of N-methylformamide in P 388 leukemia or M 5076 sarcoma in mice.

The toxicity of daily subcutaneously applied 500 mg/kg N-methylformamide (NMF) during a period of 8 days in female CD-mice was ameliorated when 100 mg/kg sodium ascorbate, 60 mg/kg menadione bisulfite or 80 mg/kg pyridoxal hydrochloride were applied simultaneously. The comparison of the daily s.c. application of 360 mg/kg NMF with the intermittent s.c. injection of 720 mg/kg NMF with an interval of 48 h in P 388 leukemia showed that the daily application of NMF induced an increase of life span of 82% whereas the intermittent schedule effected a 142% increase of life span. The simultaneous combination of 360 mg/kg NMF with 60 mg/kg sodium ascorbate applied daily caused a 133% increase of life span and the simultaneous combination of 360 mg/kg NMF with 30 mg/kg menadione sodium bisulfite lead to a 126% increase of life span. The combined daily s.c. application of 360 mg/kg NMF with 30 mg/kg pyridoxal hydrochloride induced only a minimal difference compared to the daily application of 360 mg/kg NMF alone. The combination of 720 mg/kg NMF with 120 mg/kg sodium ascorbate applied in intervals of 48 h showed a 164% increase of life span. In advanced M 5076 sarcoma the daily s.c. application of 360 mg/kg NMF effected a 82% increase of life span and the combination of 360 mg/kg NMF with 60 mg/kg sodium ascorbate effected a 135% increase of life span.

Studies on the toxicity of the antitumour agent N-methylformamide in mice.

Aspects of the toxicology of N-methylformamide (NMF), an investigational antitumour agent, were studied in mice. After injection of NMF at its LD10 (800 mg/kg) dosage the total peripheral white blood cell and platelet counts were unchanged in BALB/c mice. A mild granulocytosis was seen in this strain after administration of the LD50 (2300 mg/kg) dosage. Plasma activity of the enzyme sorbitol dehydrogenase in BDF1 mice was markedly increased after either a single injection of not less than 800 mg/kg or a chronic treatment of not less than 400 mg/kg/day over 5 days indicating the drug to be hepatotoxic. Plasma activities of L-alanine and L-aspartate aminotransferases were also increased after the chronic treatment. Chronic administration of NMF was less hepatotoxic than single dose administration of the same total dose and also increased the antitumour efficacy of NMF against the M5076 sarcoma. These results indicate that the maximum therapeutic benefit of NMF might be obtained by the use of chronic schedules and that the drug is not myelosuppressive.

Phase II trial of N-methylformamide in advanced renal cancer.

N-methylformamide (NMF) (800-1,000 mg/m2 i.v. day 1) was given to 14 patients with measurable, advanced renal cell carcinoma in this Phase II trial. Treatment was repeated every 28 days. Significant toxicities included drug-induced hepatitis along with moderate nausea and vomiting. No objective responses were seen although several patients had stable disease with treatment for prolonged periods. NMF is not an active agent in renal cell cancer when administered by this schedule.

Antitumor effect of the new rhodium (II) complex: Rh2 (form)2 (O2 CCF3)2 (H2O)2 (form = N,N'-di-p-tolyl formamidinate).

The new rhodium(II) complex Rh2(Form) (O2CCF3)2(H2O)2 (Form = N,N'-di-p-tolyl formamidinate) was evaluated for its toxicity on the rat and for its efficacy against two tumors of this animal: the Yoshida ascites sarcoma and the T8 sarcoma of Guérin. The rhodium(II) formamidinate shows very low toxicity: in fact 150 mg/kg (the highest quantity of drug soluble in 4 ml of dimenthyl sulfoxide) is not toxic for rats. We were unable to establish the lethal dose or the highest nontoxic dose since larger mounts of complex require a dose of dimethyl sulfoxide (DMSO) that is itself toxic and the compound is insoluble in other solvents such as water or Tween. Doses of rhodium(II) formamidinate, varying from 3 to 30 mg/kg, were administered once by i.p., i.v., i.m. and intratumor (i.t.) route from 1 to 7 days after i.p. injection of 10(6) Yoshida ascites sarcoma cells and subcutaneous (s.c.) implantation of approximately 300 mg (corresponding to 2-3 x 10(7) living tumor cells) of T8 sarcoma of Guérin. The compound is active when administered i.p. 24 hours after Yoshida ascites sarcoma at the smallest dose tested (3 mg/Kg), increasing the average life span of 62.3% and allowing the survival of 50% of the rats. It is also active when administered i.p. at the highest dose tested (30 mg/Kg) 7 days after tumor cell challenge, increasing the average life span in 43.8% and allowing survival in 20% of the rats; it is not active after i.v. or i.m administration.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of unithiol on the antineoplastic and antimetastatic activity of N-methylformamide]. / Vliianie unitiola na protivoopukholevuiu i antimetastaticheskuiu aktivnost' N-metilformamida.

Antitumor and antimetastatic properties of N-methyl formamide--an agent related to differentiation of tumoral cells and unithiol, official detoxicating drug containing SH-groups were studied in C57Bl/6 mice inoculated with Lewis's lung carcinoma. The drugs were administered intraperitoneally into animals at days 1, 4, 7, 13 and 16 after carcinoma inoculation and their effects were evaluated at day 19. Single administration of unithiol, 5 mg/kg body weight, did not affect tumor growth and metastases spreading. At the same time, N-methyl formamide (single administration of 300 mg/kg body weight) inhibited tumor growth and decreased 5-fold an amount of spontaneous metastases in lungs. However, the antitumor and antimetastatic activities of N-methyl formamide were decreased after simultaneous administration with unithiol. Importance of SH-groups in therapeutic effects of N-methyl formamide is discussed.

[Inhibition of transplantable tumors in mice by monomethylformamide]. / Zaderzhka rosta perevivnykh opukholei myshei monometil-formamidom.

The paper discusses the effect of a cell differentiation-inducing agent--monomethylformamide--on the growth of ascites hepatoma 22A, Ehrlich ascites tumor, thymoma EL-4, leukemia L1210, Lewis lung carcinoma and hemocytoblastosis La. A single injection of the drug into tumor-bearing mice inhibited the growth of the said neoplasms as shown by cell levels in ascites tumors, node size of Lewis lung carcinoma and survival in animals with hemocytoblastosis La. The analysis of the kinetics of inhibition of growth to be transient. For both tumors, the effect of 0.25 g/kg body weight and more showed exponential growth.

The inhibitor of 20-HETE synthesis, TS-011, improves cerebral microcirculatory autoregulation impaired by middle cerebral artery occlusion in mice.

BACKGROUND AND PURPOSE: 20-Hydroxyeicosatetraenoic acid is a potent vasoconstrictor that contributes to cerebral ischaemia. An inhibitor of 20-Hydroxyeicosatetraenoic acid synthesis, TS-011, reduces infarct volume and improves neurological deficits in animal stroke models. However, little is known about how TS-011 affects the microvessels in ischaemic brain. Here, we investigated the effect of TS-011 on microvessels after cerebral ischaemia. EXPERIMENTAL APPROACH: TS-011 (0.3 mg·kg(-1) ) or a vehicle was infused intravenously for 1 h every 6 h in a mouse model of stroke, induced by transient occlusion of the middle cerebral artery occlusion following photothrombosis. The cerebral blood flow velocity and the vascular perfusion area of the peri-infarct microvessels were measured using in vivo two-photon imaging. KEY RESULTS: The cerebral blood flow velocities in the peri-infarct microvessels decreased at 1 and 7 h after reperfusion, followed by an increase at 24 h after reperfusion in the vehicle-treated mice. We found that TS-011 significantly inhibited both the decrease and the increase in the blood flow velocities in the peri-infarct microvessels seen in the vehicle-treated mice after reperfusion. In addition, TS-011 significantly inhibited the reduction in the microvascular perfusion area after reperfusion, compared with the vehicle-treated group. Moreover, TS-011 significantly reduced the infarct volume by 40% at 72 h after middle cerebral artery occlusion. CONCLUSIONS AND IMPLICATIONS: These findings demonstrated that infusion of TS-011 improved defects in the autoregulation of peri-infarct microcirculation and reduced the infarct volume. Our results could be relevant to the treatment of cerebral ischaemia.