Marked Antitumour Activity Research Articles

Human CD4+ iNKT cell adoptive immunotherapy induces anti-tumour responses against CD1d-negative EBV-driven B lymphoma.

Invariant natural killer T (iNKT) cells are a conserved population of innate T lymphocytes that are uniquely suitable as off-the-shelf cellular immunotherapies due to their lack of alloreactivity. Two major subpopulations of human iNKT cells have been delineated, a CD4- subset that has a TH1/cytolytic profile, and a CD4+ subset that appears polyfunctional and can produce both regulatory and immunostimulatory cytokines. Whether these two subsets differ in anti-tumour effects is not known. Using live cell imaging, we found that CD4- iNKT cells limited growth of CD1d+ Epstein-Barr virus (EBV)-infected B-lymphoblastoid spheroids in vitro, whereas CD4+ iNKT cells showed little or no direct anti-tumour activity. However, the effects of the two subsets were reversed when we tested them as adoptive immunotherapies in vivo using a xenograft model of EBV-driven human B cell lymphoma. We found that EBV-infected B cells down-regulated CD1d in vivo, and administering CD4- iNKT cells had no discernable impact on tumour mass. In contrast, xenotransplanted mice bearing lymphomas showed rapid reduction in tumour mass after administering CD4+ iNKT cells. Immunotherapeutic CD4+ iNKT cells trafficked to both spleen and tumour and were associated with subsequently enhanced responses of xenotransplanted human T cells against EBV. CD4+ iNKT cells also had adjuvant-like effects on monocyte-derived DCs and promoted antigen-dependent responses of human T cells in vitro. These results show that allogeneic CD4+ iNKT cellular immunotherapy leads to marked anti-tumour activity through indirect pathways that do not require tumour cell CD1d expression and that are associated with enhanced activity of antigen-specific T cells.

Therapeutic efficacy of 225Ac-PSMA-617 targeted alpha therapy in patients of metastatic castrate resistant prostate cancer after taxane-based chemotherapy.

225Ac-PSMA-617 therapy has shown good response in many recent studies. We report our experience of targeted alpha therapy with 225Ac-PSMA-617 in mCRPC patients who have failed therapy with taxanes. Thirty-eight patients with CRPC with progressive disease following at least one taxane-based chemotherapy received 225Ac-PSMA-617 between July 2017 and Nov 2019. Primary end point was a composite 50% PSA and radiological response. Secondary endpoints were PFS, OS, and changes in QOL. The differences in outcomes between patients with skeletal and lymph-node metastases versus those with visceral metastases were also studied. A composite response by predetermined criteria was observed in 25 (66%) of 38 patients. The median PFS was 8months (95% CI 5.3-10.6months). Median overall survival was 12months (95% CI 9.1-14.9) with 16 patients alive at the time of censorship. There was no difference in response rates or survival statistics between patients with visceral metastases versus those with only bone and lymph-node metastases (Chi-square 1.51, df 1, Sig 0.218). The most common adverse effect was xerostomia. On the QOL Symptom score, Pain, Fatigue Insomnia, and constipation showed a significant improvement as compared to baseline. 225Ac-PSMA-617 is a safe and tolerable treatment option for mCRPC that demonstrates marked anti-tumour activity with improvement in quality of life even in patients of metastatic CRPC who have been previously treated with taxane-based chemotherapy.

Impact of hypoxia on chemoresistance of mesothelioma mediated by the proton-coupled folate transporter, and preclinical activity of new anti-LDH-A compounds

BackgroundExpression of proton-coupled folate transporter (PCFT) is associated with survival of mesothelioma patients treated with pemetrexed, and is reduced by hypoxia, prompting studies to elucidate their correlation.MethodsModulation of glycolytic gene expression was evaluated by PCR arrays in tumour cells and primary cultures growing under hypoxia, in spheroids and after PCFT silencing. Inhibitors of lactate dehydrogenase (LDH-A) were tested in vitro and in vivo. LDH-A expression was determined in tissue microarrays of radically resected malignant pleural mesothelioma (MPM, N = 33) and diffuse peritoneal mesothelioma (DMPM, N = 56) patients.ResultsOverexpression of hypoxia marker CAIX was associated with low PCFT expression and decreased MPM cell growth inhibition by pemetrexed. Through integration of PCR arrays in hypoxic cells and spheroids and following PCFT silencing, we identified the upregulation of LDH-A, which correlated with shorter survival of MPM and DMPM patients. Novel LDH-A inhibitors enhanced spheroid disintegration and displayed synergistic effects with pemetrexed in MPM and gemcitabine in DMPM cells. Studies with bioluminescent hypoxic orthotopic and subcutaneous DMPM athymic-mice models revealed the marked antitumour activity of the LDH-A inhibitor NHI-Glc-2, alone or combined with gemcitabine.ConclusionsThis study provides novel insights into hypoxia/PCFT-dependent chemoresistance, unravelling the potential prognostic value of LDH-A, and demonstrating the preclinical activity of LDH-A inhibitors.

A novel oral micellar fenretinide formulation with enhanced bioavailability and antitumour activity against multiple tumours from cancer stem cells

BackgroundAn increasing number of anticancer agents has been proposed in recent years with the attempt to overcome treatment-resistant cancer cells and particularly cancer stem cells (CSC), the major culprits for tumour resistance and recurrence. However, a huge obstacle to treatment success is the ineffective delivery of drugs within the tumour environment due to limited solubility, short circulation time or inconsistent stability of compounds that, together with concomitant dose-limiting systemic toxicity, contribute to hamper the achievement of therapeutic drug concentrations. The synthetic retinoid Fenretinide (4-hydroxy (phenyl)retinamide; 4-HPR) formerly emerged as a promising anticancer agent based on pre-clinical and clinical studies. However, a major limitation of fenretinide is traditionally represented by its poor aqueous solubility/bioavailability due to its hydrophobic nature, that undermined the clinical success of previous clinical trials.MethodsHere, we developed a novel nano-micellar fenretinide formulation called bionanofenretinide (Bio-nFeR), based on drug encapsulation in an ion-pair stabilized lipid matrix, with the aim to raise fenretinide bioavailability and antitumour efficacy.ResultsBio-nFeR displayed marked antitumour activity against lung, colon and melanoma CSC both in vitro and in tumour xenografts, in absence of mice toxicity. Bio-nFeR is suitable for oral administration, reaching therapeutic concentrations within tumours and an unprecedented therapeutic activity in vivo as single agent.ConclusionAltogether, our results indicate Bio-nFeR as a novel anticancer agent with low toxicity and high activity against tumourigenic cells, potentially useful for the treatment of solid tumours of multiple origin.

Abstract A16: A drug combination screen identifies taxanes as synergistic agents with the oral IAP inhibitor Debio 1143 in non-small cell lung cancer cells.

Abstract Background: Drug resistance is a major problem in cancer therapy. The combination of drugs targeting simultaneously multiple critical nodes of the signalling networks controlling growth and survival of cancer cells is necessary to achieve long-lasting responses. The members of the Inhibitor of apoptosis protein (IAP) family are key negative regulators of programmed cell death. Their frequent overexpression in most cancer types contributes to tumor cell survival and resistance to cancer therapy making IAPs attractive therapeutic targets. The oral monovalent SMAC mimetic, Debio 1143/AT-406, functions as an antagonist of multiple IAP proteins (cIAP1/2 and XIAP) and is currently in clinical development for cancer treatment. The goal of this study is to identify novel synergistic combination partners with Debio 1143 in non-small cell lung cancer (NSCLC). Material and Methods: An in vitro high-throughput combination screen was performed using 6 human NSCLC cell lines bearing various genetic alterations. Debio 1143 was pairwise combined with 128 commercially available oncology compounds in a cell viability assay. To identify supra-additive drug combinations, the dose-response curves were analysed using the Bliss independence method. Synergistic combinations were further studied using tumor xenograft mouse models. Results: Among several interesting combinations, we observed strong synergism of Debio 1143 combined with docetaxel or paclitaxel, two standard-of-care drugs in NSCLC. The beneficial effect of the combination between Debio 1143 and taxanes was further validated in multiple mouse cancer xenografts where the combination caused marked anti-tumour activity that was superior to either monotherapy. Conclusion: These findings underline the feasibility of using in vitro high-throughput screening for the discovery of novel drug combinations with increased anti-tumour efficacy in vivo. Furthermore, they provide a rationale for the combination of the SMAC mimetic Debio 1143 with taxanes and are the basis for ongoing clinical trials in several cancer types. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A16. Citation Format: Casey G. Langdon, Norbert Wiedemann, Mathew A. Held, James T. Platt, Frédéric Lévy, Claudio Zanna, Grégoire Vuagniaux, Mel Sorensen, Shaomeng Wang, Marcus W. Bosenberg, David F. Stern. A drug combination screen identifies taxanes as synergistic agents with the oral IAP inhibitor Debio 1143 in non-small cell lung cancer cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A16.

Effect of crizotinib on overall survival in patients with advanced non-small-cell lung cancer harbouring ALK gene rearrangement: a retrospective analysis.

ALK gene rearrangement defines a new molecular subtype of non-small-cell lung cancer (NSCLC). In a recent phase 1 clinical trial, the ALK tyrosine-kinase inhibitor (TKI) crizotinib showed marked antitumour activity in patients with advanced, ALK-positive NSCLC. To assess whether crizotinib affects overall survival in these patients, we did a retrospective study comparing survival outcomes in crizotinib-treated patients in the trial and crizotinib-naive controls screened during the same time period. We examined overall survival in patients with advanced, ALK-positive NSCLC who enrolled in the phase 1 clinical trial of crizotinib, focusing on the cohort of 82 patients who had enrolled through Feb 10, 2010. For comparators, we identified 36 ALK-positive patients from trial sites who were not given crizotinib (ALK-positive controls), 67 patients without ALK rearrangement but positive for EGFR mutation, and 253 wild-type patients lacking either ALK rearrangement or EGFR mutation. To assess differences in overall survival, we assessed subsets of clinically comparable ALK-positive and ALK-negative patients. Among 82 ALK-positive patients who were given crizotinib, median overall survival from initiation of crizotinib has not been reached (95% CI 17 months to not reached); 1-year overall survival was 74% (95% CI 63-82), and 2-year overall survival was 54% (40-66). Overall survival did not differ based on age, sex, smoking history, or ethnic origin. Survival in 30 ALK-positive patients who were given crizotinib in the second-line or third-line setting was significantly longer than in 23 ALK-positive controls given any second-line therapy (median overall survival not reached [95% CI 14 months to not reached] vs 6 months [4-17], 1-year overall survival 70% [95% CI 50-83] vs 44% [23-64], and 2-year overall survival 55% [33-72] vs 12% [2-30]; hazard ratio 0·36, 95% CI 0·17-0·75; p=0·004). Survival in 56 crizotinib-treated, ALK-positive patients was similar to that in 63 ALK-negative, EGFR-positive patients given EGFR TKI therapy (median overall survival not reached [95% CI 17 months to not reached] vs 24 months [15-34], 1-year overall survival 71% [95% CI 58-81] vs 74% [61-83], and 2-year overall survival 57% [40-71] vs 52% [38-65]; p=0·786), whereas survival in 36 crizotinib-naive, ALK-positive controls was similar to that in 253 wild-type controls (median overall survival 20 months [95% CI 13-26] vs 15 months [13-17]; p=0·244). In patients with advanced, ALK-positive NSCLC, crizotinib therapy is associated with improved survival compared with that of crizotinib-naive controls. ALK rearrangement is not a favourable prognostic factor in advanced NSCLC. Pfizer Inc, V Foundation for Cancer Research.

Marked anti-tumour activity of the combination of YM155, a novel survivin suppressant, and platinum-based drugs

Background:Survivin, a member of the inhibitor of apoptosis protein family, is an attractive target for cancer therapy. We have now investigated the effects of the combination of YM155, a novel small-molecule inhibitor of survivin expression, and platinum compounds (cisplatin and carboplatin) on human non-small cell lung cancer (NSCLC) cell lines.Methods:The anti-cancer efficacy of YM155 in combination with platinum compounds was evaluated on the basis of cell death and progression of tumour xenografts. Platinum compound-induced DNA damage was evaluated by immunofluorescence analysis of histone γ-H2AX.Results:Immunofluorescence analysis of histone γ-H2AX showed that YM155 delayed the repair of double-strand breaks induced in nuclear DNA by platinum compounds. The combination of YM155 and platinum compounds also induced synergistic increases both in the number of apoptotic cells and in the activity of caspase-3. Finally, combination therapy with YM155 and platinum compounds delayed the growth of NSCLC tumour xenografts in nude mice to an extent greater than that apparent with either treatment modality alone.Conclusion:These results suggest that YM155 sensitises tumour cells to platinum compounds both in vitro and in vivo, and that this effect is likely attributable to the inhibition of DNA repair and consequent enhancement of apoptosis.

The sodium pump α1 sub‐unit: a disease progression–related target for metastatic melanoma treatment

Melanomas remain associated with dismal prognosis because they are naturally resistant to apoptosis and they markedly metastasize. Up-regulated expression of sodium pump α sub-units has previously been demonstrated when comparing metastatic to non-metastatic melanomas. Our previous data revealed that impairing sodium pump α1 activity by means of selective ligands, that are cardiotonic steroids, markedly impairs cell migration and kills apoptosis-resistant cancer cells. The objective of this study was to determine the expression levels of sodium pump α sub-units in melanoma clinical samples and cell lines and also to characterize the role of α1 sub-units in melanoma cell biology. Quantitative RT-PCR, Western blotting and immunohistochemistry were used to determine the expression levels of sodium pump α sub-units. In vitro cytotoxicity of various cardenolides and of an anti-α1 siRNA was evaluated by means of MTT assay, quantitative videomicroscopy and through apoptosis assays. The in vivo activity of a novel cardenolide UNBS1450 was evaluated in a melanoma brain metastasis model. Our data show that all investigated human melanoma cell lines expressed high levels of the α1 sub-unit, and 33% of human melanomas displayed significant α1 sub-unit expression in correlation with the Breslow index. Furthermore, cardenolides (notably UNBS1450; currently in Phase I clinical trials) displayed marked anti-tumour effects against melanomas in vitro. This activity was closely paralleled by decreases in cMyc expression and by increases in apoptotic features. UNBS1450 also displayed marked anti-tumour activity in the aggressive human metastatic brain melanoma model in vivo. The α1 sodium pump sub-unit could represent a potential novel target for combating melanoma.

Antimicrobial Activity of Two Antitumour Agents and Ribonucleotide Reductase Inhibitors, Pyridine-2-carboxaldehyde Thiosemicarbazone and the Acetate Form of its Copper(II) Chelate

Some copper chelates have potent antitumour activity, and in some cases also the free ligands have activity in vivo. Yet, little is known about their antimicrobial properties. Copper(II) chelates of the thiosemicarbazones of a-N-heterocyclic carboxaldehydes constitute one important group of such agents, also their ligands having marked antitumour activity. Both the ligands and chelates inhibit ribonucleotide reductase. Some ligands have been or are under clinical trials as antineoplastic agents. I report here a study on the antimicrobial properties of the prototype compounds of this group, pyridine-2-carboxaldehyde thiosemicarbazone and its copper(II) chelate. They were tested against nine microbes, including bacteria (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus lactis), yeasts (Candida albicans and Saccharomyces cerevisiae) and one mold (Aspergillus niger). Two clinical isolates of Bacillus sp. and one reference strain were also studied. Both the ligand and the chelate had marked activity. The ligand displayed considerable activity against all bacteria except for S. lactis, and its activity against E. coli and P. aeruginosa was that high that practical applications might be considued. It was highly active against A. niger and moderately active against C. albicans. The chelate was highly active against S. epidermidis and S. cerevisiae. Both compounds inhibited the clinical isolates markedly. Since some related ligands have been or are in clinical trials on humans or are entering them, their route to clinical use, also as antimicrobials, might be much more straightforward than that of substances, whose toxicity in humans is wholly unexplored.

Bioactive brominated diterpenes from the marine red alga Jania Rubens (L.) Lamx.

Seven brominated diterpenes of the parguerene and isoparguerene series were isolated for the first time from the red alga Jania rubens (L.) Lamx., collected from the Red Sea coast at Hurghada, Egypt. The diterpenes were identified as isoparguerol (1), isoparguerol-16-acetate (2), isoparguerol-7,16-diacetate (3), parguerol-16-acetate (4), parguerol-7,16-diacetate (5), deoxyparguerol (6) and deoxyparguerol-7-acetate (7). The isolated diterpenes had a marked antitumour activity. Isoparguerol derivatives were slightly more effective than parguerol derivatives. Moreover, the data implied that the cytotoxicity of these compounds were dependent on the number of acetoxy groups. Also, anthelmintic activities of the isolated compounds on earthworms (Allolobophora caliginosa) were studied.

Synergistic effects of F 11782, a novel dual inhibitor of topoisomerases I and II, in combination with other anticancer agents.

F 11782, or 2',3'-bis-pentafluorophenoxyacetyl-4',6'-ethylidine-beta- D-glucoside of 4'-phosphate-4'-dimethylepipodophyllotoxin 2 N-methyl glucamine salt, a novel dual catalytic inhibitor of topoisomerases I and II, characterized by marked antitumour activity in vivo in a series of experimental murine and human tumours, has been selected for further development. This preclinical study was undertaken to investigate its potential for inclusion in combination chemotherapy regimens. The in vitro cytotoxicity of F 11782 incubated simultaneously with the following drugs was investigated: aclarubicin, cisplatin, doxorubicin, etoposide, 5-fluorouracil, mitomycin C, paclitaxel, topotecan or vinorelbine. The combinations were first evaluated in vitro against the GCT27 human testicular teratoma cell line and then against the A549 human non-small cell lung cancer cell line using median effect analysis. F 11782 in combination with cisplatin, mitomycin C, etoposide or doxorubicin showed synergistic cytotoxicity against both cell lines. Moreover, F 11782 combined with cisplatin or mitomycin C showed antitumour activity in vivo against P388 murine leukaemia grafted intravenously. Such synergy might have resulted from the identified nucleotide excision repair inhibitory activity of F 11782. F 11782 appears to be a promising candidate for combination chemotherapy, especially with DNA-damaging agents.

In vitro synergistic effects of vinflunine, a novel fluorinated vinca alkaloid, in combination with other anticancer drugs.

Vinflunine (20'-20'-difluoro-3',4'-dihydrovinorelbine), a novel derivative of vinorelbine characterized by marked antitumour activity in vivo in a series of experimental murine and human tumours is currently undergoing phase I evaluation. To investigate its potential for inclusion in combination chemotherapy regimens, this preclinical study was undertaken. The in vitro cytotoxicity of vinflunine incubated simultaneously with one of the following drugs was investigated: camptothecin, cisplatin, doxorubicin, etoposide, 5-fluorouracil, gemcitabine, mitomycin C, paclitaxel or vinorelbine. The combinations were first evaluated in vitro against the A549 human non-small-cell lung cancer cell line using median-effect analyses. The results revealed synergistic cytotoxicity when vinflunine was combined with cisplatin, mitomycin C, doxorubicin or 5-fluorouracil. Synergy was also observed when testing similar combinations against CCRF-CEM human leukaemia cells. Finally, these findings were comparable with those resulting from such combinations involving vinorelbine instead of vinflunine. Vinflunine appears a promising candidate for combining with other anticancer drugs.

Dose-finding study of irinotecan and cisplatin plus concurrent radiotherapy for unresectable stage III non-small-cell lung cancer [seecomments

Irinotecan hydrochloride (CPT-11) shows marked anti-tumour activity alone and in combination with cisplatin in non-small-cell lung cancer (NSCLC). It is necessary to investigate combined-modality therapy including novel effective anti-cancer agents to improve long-term survival of patients with unresectable stage III NSCLC. A phase I/II study of concurrent chemoradiotherapy with CPT-11 and cisplatin was conducted to determine the maximum tolerated dose (MTD) and efficacy in this group of patients. Thirteen previously untreated patients with unresectable stage IIIA/B NSCLC were enrolled and efficacy and toxicity was evaluated in 12 of them; one patient was ineligible. Chemotherapy was repeated every 4 weeks for three courses. Radiation therapy was started on day 2 of the first course of chemotherapy and 60 Gy in 30 fractions was given over 6 weeks. Four of six patients enrolled at level 1 completed the scheduled treatment. Another two received only one and two courses of chemotherapy as a result of persistent leucopenia and neutropenic fever respectively. Three of six patients given level 2 therapy completed the scheduled treatment. Another three received only one and two courses of chemotherapy, two refused treatment because of diarrhoea and one died of pneumonia. Radiation therapy was inadequate in these three patients. As the CPT-11 dose intensity in this trial was low, because of the necessity of omitting CPT-11 administration on days 8 and/or 15 as a result of leucopenia or diarrhoea, and the low radiation therapy completion rate, the trial was discontinued at level 2. Five patients at level 1 and three at level 2 showed partial responses, an overall response rate of 67%. Although neither MTD nor dose-limiting toxicity could be identified, chemotherapy with CPT-11 and cisplatin plus concurrent radiation therapy was deemed unacceptable. We are now conducting a phase I/II study of chemotherapy using CPT-11 as a single agent in combination with radiation therapy.

Anti-(epidermal growth factor) receptor monoclonal antibodies for the induction of antibody-dependent cell-mediated cytotoxicity against squamous cell carcinoma lines of the head and neck.

Squamous cell carcinomas of the head and neck (SCCHN) frequently display high levels of the epidermal growth factor receptor (EGFR). Since EGFR is expressed on the cell surface it may form a suitable target for anticancer therapy with anti-receptor monoclonal antibodies (mAb). Besides the interference with receptor/ligand interactions, binding of mAb to EGFR leads to immunoglobulin-coated tumour cells that may induce or enhance non-specific immune effector mechanisms like antibody-dependent cell-mediated cytotoxicity (ADCC). In established cell lines of SCCHN (UM-SCC 11B, 14C, 22B, and 8029 NA) we investigated the antitumour activity of allogeneic peripheral blood mononuclear cells (PBMC) in combination with rat (ICR 62), mouse (EMD 55900), and humanized (EMD 72000) anti-EGFR mAb. In addition, autologous PBMC were available for tumour line UD-SCC 4. The EGFR protein content of the tumour cell lines ranged between 170 fmol/mg protein and 8100 fmol/mg protein, and MCF-7 cells served as receptor-negative controls. PBMC activity against SCCHN targets was determined in 96-well microtitre-plate monolayer cultures by the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after coincubation for 4 h, 24 h and 72 h at effector target ratios of 1:1, 5:1, 10:1 and 20:1. PBMC subpopulations were obtained by macrophage depletion (plastic adherence) or natural killer (NK) cell enrichment (magnetic bead negative selection). Prolonged time of exposure and increased effector:target ratios revealed marked antitumour activity of PBMC alone. This non-specific immune destruction was enhanced considerably by humanized and rat, but not mouse anti-EGFR mAb. Increased EGFR protein in tumour cells partly correlated with an intensification of ADCC but was accompanied by decreased primary PBMC cytotoxicity. The utilization of PBMC subpopulations suggested a mainly NK-cell-mediated ADCC, which appeared to benefit directly or indirectly, e.g. via the secretion of cytokines, from other PBMC components. In conclusion, humanized (EMD 72000) and rat (ICR 62) anti-EGFR mAb were able to generate strong antitumour ADCC in target monolayers of SCCHN.

Metal chelates as anti-cancer agents. II cytotoxic action of palladium and platinum complexes of 6-mercaptopurine and thioguanine

The metal complexes Pd(MP)2.2H2O, Pt(MP)2H2O (MPH=6-mercaptopurine), Pt(AMP2.3H2O and Pd3(AMP)4Cl2(AMPH).4H2O (AMPH=thioguanine) have been isolated. They were screened for anti-tumour activity in the L-1210 lymphoid leukaemia test system in mice. All 4 show marked anti-tumour activity, the complex Pt(AMP)2.3H2O giving a T/C of 185 at the optimum dosage. However, the anti-tumour activity of the metal complexes is somewhat less than that shown by the parent purines under the same conditions.

Cytotoxic compounds. XVII. O-, m-, and p-(bis-2-chloroethylamino)phenol, p-(N-(2-chloroethyl)methylamino)phenol, NN-bis-2-chloroethyl-p-phenylenediamine, and NN-bis-2-chloroethyl-N'-methyl-p-phenylenediamine as sources of biologically active carbamates.

New or improved syntheses are reported of the nitrogen mustards named in the title, and of methyl m-(bis-2-chloroethylamino)-p-hydroxybenzoate. By reactions of the amines with aryl chloroformates, or of the phenols with aryl isocyanates or with isocyanates derived from α-amino-esters, carbamates containing alkyl, chloro-, alkoxy-, hydroxy-, methoxycarbonyl, carboxy-, acetyl, and sulphamoyl groups are obtained. Some of these have shown marked anti-tumour activity. p-(Bis-2-chloroethylamino)phenyl chloroformate has been prepared; it provides an alternative route to mustard carbamates. Some carbamates of the lachrymator type have been synthesised from p-aminophenacyl chloride.

Antineoplastic Principle Derived fromCarduus Benedictus

Juices extracted from fresh plant material of Carduus benedictus of the botanical family of Compositae have been found to contain substances exhibiting marked anti-tumour activity.

Carboxymethylpachymaran, a new water soluble polysaccharide with marked antitumour activity.

WE have reported that the polysaccharides lentinan1,2 and pachymaran3 strongly inhibit the growth of sarcoma 180 transplanted in mice, and that they could be considered as excellent immune-accelerators of cell-mediated responses4,5. It is difficult, however, to dissolve them in water and to label them with isotopes, and their use in biological investigations can therefore be troublesome. We have now prepared a water soluble polysaccharide with marked antitumour activity, known as carboxymethylpachymaran ([α]20D = −2.8°; c = 1 in H2O; solubility, 6.7 g/100 ml. H2O at 30° C) which can be labelled at the carboxymethyl residue with 14C so that its distribution at the cellular and subcellular level can be investigated.

Spermatic toxicity of diazoacetyl-glycine amide (DGA) in mice

Summary Female Swiss albino mice were mated with males previously treated with DGA. Whereas a dose of 500 mg/kg/day for 4. days had no appreciable effect, the treatment of the males with 700 mg/kg/ day for 4 days caused a decrease in the number of litters and newborns. DGA is a derivative of diazoacetyl-glycine, with the following chemical structure: N N CH CO NH CH2 CO NH2 It has a marked antitumour activity on the ascitic forms of Sarcoma 180 and Ehrlich carcinoma and on the Galliera rat sarcoma, and a more limited tumour-inhibiting activity on the solid forms of Sarcoma 180 and Ehrlich carcinoma, and on the Harding-Passey melanoma ( Baldini and Brambilla, 1966 ). It also has a remarkable immunodepressant activity. Treatments with DGA significantly prolong the mean survival time of skin graft in H-2 incompatible mice and are effective in allowing the growth of L1210 Leukemia allgrafts in the C$7BL/6 strain and the development of Ehrlich ascites carcinoma in immunized mice ( Brambilla et al., 1970 ). The diazoacetyl-glycine derivatives have a noteworthy toxic activity on many rapidly growing cells and tissues. When administered to animals, they cause bone hypoplasia, marked lymphocytopenia, damage to the gastric and intestinal epithelium, but fail to inhibit rat liver regeneration ( Brambilla et al., 1969 ). The aim of the present investigation was to examine the possible toxic action of DGA on spermatogenesis, which requires synthesis of proteins and nucleic acids, a potential target for the action of DGA.

Cancerostatic protein components from Viscum album

A protein fraction ofViscum album, posessing marked anti-tumour activity in the experimental animal, is described. The isolation procedure and some physical and chemical properties are presented.