Phase II study of XR 5000 (DACA), an inhibitor of topoisomerase I and II, administered as a 120-h infusion in patients with non-small cell lung cancer

Updates on the versatile quinoline heterocycles as anticancer agents

Quinoline motifs have befallen significant molecules due to their assortment of interest in medicine, chemical synthesis, coordination chemistry, also in the field of applied chemistry. Therefore, various researchers have produced these molecules as objective structures and studied their natal potential. The current chapter endows with concise attention about cancer, anticancer agents, sources (natural) of quinoline, and together with an innovative scope of quinoline-related medicines. Further, the present section gives knowledge concerned with the anticancer activity of synthesized quinolines and their derivatives.

A comprehensive review on the biological interest of quinoline and its derivatives

Amongst heterocyclic compounds, quinoline is an advantaged scaffold that appears as a significant assembly motif for the development of new drug entities. Quinoline and its derivatives tested with diverse biological activity constitute an important class of compounds for new drug development. Therefore, many scientific communities have developed these compounds as intent structure and evaluated their biological activities. The present, review provides brief natural sources of quinoline and including a new extent of quinoline-based marketed drugs. This review also confers information about the biological activities of quinoline derivatives such as antibacterial, antifungal, antimycobacterial, antiviral, anti-protozoal, antimalarial, anticancer, cardiovascular, CNS effects, antioxidant, anticonvulsant, analgesic, anti-inflammatory, anthelmintic and miscellaneous activities.

Acridine Derivatives as Inhibitors of the IRE1α-XBP1 Pathway Are Cytotoxic to Human Multiple Myeloma

Using a luciferase reporter-based high-throughput chemical library screen and topological data analysis, we identified N-acridine-9-yl-N',N'-dimethylpropane-1,3-diamine (DAPA) as an inhibitor of the inositol requiring kinase 1α (IRE1α)-X-box binding protein-1 (XBP1) pathway of the unfolded protein response. We designed a collection of analogues based on the structure of DAPA to explore structure-activity relationships and identified N(9)-(3-(dimethylamino)propyl)-N(3),N(3),N(6),N(6)-tetramethylacridine-3,6,9-triamine (3,6-DMAD), with 3,6-dimethylamino substitution on the chromophore, as a potent inhibitor. 3,6-DMAD inhibited both IRE1α oligomerization and in vitro endoribonuclease (RNase) activity, whereas the other analogues only blocked IRE1α oligomerization. Consistent with the inhibition of IRE1α-mediated XBP1 splicing, which is critical for multiple myeloma cell survival, these analogues were cytotoxic to multiple myeloma cell lines. Furthermore, 3,6-DMAD inhibited XBP1 splicing in vivo and the growth of multiple myeloma tumor xenografts. Our study not only confirmed the utilization of topological data analysis in drug discovery but also identified a class of compounds with a unique mechanism of action as potent IRE1α-XBP1 inhibitors in the treatment of multiple myeloma. Mol Cancer Ther; 15(9); 2055-65. ©2016 AACR.

The solution structure of bis(phenazine-1-carboxamide)-DNA complexes: MLN 944 binding corrected and extended

MLN 944 is a bisintercalating DNA-binding antitumor agent known to be a template inhibitor of transcription. Previous (1) H NMR studies of its d(ATGCAT)2 complex concluded that its phenazine chromophores are protonated. However, we find that this is not so, which has important consequences for the charged state of the ligand, for the orientation of its 1-carboxamide group in the complex, and for the details of the interaction of its protonated interchromophore linker with the DNA base pairs. Here, we report a corrected solution structure of the MLN 944-d(ATGCAT)2 complex, and extend the study to complexes with d(TATGCATA)2 , and d(TACGCGTA)2 , using a variety of (1) H and (31) P NMR methods and molecular dynamics simulations employing the AMBER 12 force field. We find that for all three complexes MLN 944 binds as a dication, in which the chromophores are uncharged, in the DNA major groove spanning the central 2 GC base pairs in a manner that maintains the dyad symmetry of the DNA. The carboxamide group lies in the plane of the chromophore, its NH making hydrogen bonding interactions with the phenazine N10 nitrogen, and the protonated linkers form hydrogen bonds with the O6 atom of guanine. The dynamics simulations reveal extensive solvent interactions involving the linker amines, the carboxamide group, and the DNA bases.

Why are we failing to implement imaging studies with radiolabelled new molecular entities in early oncology drug development?

In early drug development advanced imaging techniques can help with progressing new molecular entities (NME) to subsequent phases of drug development and thus reduce attrition. However, several organizational, operational, and regulatory hurdles pose a significant barrier, potentially limiting the impact these techniques can have on modern drug development. Positron emission tomography (PET) of radiolabelled NME is arguably the best example of a complex technique with a potential to deliver unique decision-making data in small cohorts of subjects. However, to realise this potential the impediments to timely inclusion of PET into the drug development process must be overcome. In the present paper, we discuss the value of PET imaging with radiolabelled NME during early anticancer drug development, as exemplified with one such NME. We outline the multiple hurdles and propose options on how to streamline the organizational steps for future studies.

Novel synthetic 2-amino-10-(3,5-dimethoxy)benzyl-9(10H)-acridinone derivatives as potent DNA-binding antiproliferative agents

A series of novel 9(10H)-acridinone derivatives with terminal amino substituents at C2 position on the acridinone ring were synthesized and studied for their antiproliferative activity and underlying mechanisms. These compounds demonstrated promising cytotoxicity to leukemia cells CCRF-CEM, displaying IC(50) values in the low micromolar range. Structure-activity relationships (SAR) indicated that the compound 6d bearing a pyrrolidine substituent and 8a with a methyl ammonium side chain displayed higher cytotoxicity to CCRF-CEM cells and also solid tumor cells A549, HepG2, and MCF7. Furthermore, the compounds 6d and 8a had strong binding activity to calf thymus DNA (ct DNA), as detected by UV absorption and fluorescence quenching assays, but limited inhibitory activity to human topoisomerase 1 (topo 1). Taken together, this study discovered a series of new synthetic 9(10H)-acridinone derivatives with potent DNA binding and anticancer activity.

In vitro assessment of novel transcription inhibitors and topoisomerase poisons in rhabdomyosarcoma cell lines

PURPOSE

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Current chemotherapy regimes include the topoisomerase II poison etoposide and the transcription inhibitor actinomycin D. Poor clinical response necessitate identification of new agents to improve patient outcomes.

METHODS

We assessed the in vitro cytotoxicity (MTT assay) of DNA intercalating agents in five established human RMS cell lines. These include novel classes of transcription inhibitors and topoisomerase poisons, previously shown to have potential as anti-cancer agents.

RESULTS

Amongst the former agents, bisintercalating bis(9-aminoacridine-4-carboxamides) linked through the 9-position, and bis(phenazine-1-carboxamides) linked via their side chains, are compared with established transcription inhibitors. Amongst the latter, monofunctional acridine-4-carboxamides related to N-[2-(dimethylamino)ethyl]acridine-4-carboxamide, DACA, are compared with established topoisomerase poisons.

CONCLUSIONS

Our findings specifically highlight the topoisomerase poison 9-amino-DACA, its 5-methylsulphone derivative, AS-DACA, and the bis(phenazine-1-carboxamide) transcription inhibitor MLN944/XR5944, currently in phase I trial, as candidates for further research into new agents for the treatment of RMS.

Effect of linkage geometry on biological activity in thiourea- and guanidine-substituted acridines and platinum-acridines

Novel thiourea- and guanidine-modified acridine-4-carboxamides (4, 7) and a corresponding platinum-intercalator conjugate (4') have been synthesized and evaluated as cytotoxic agents in human promyelocytic leukemia, HL-60, and a non-small cell lung cancer, NCI-H460. Modification of thiourea sulfur in derivative 4 with a DNA platinating moiety, giving 4', resulted in a pronounced cytotoxic enhancement, and the conjugate proved to be the most active of the newly synthesized compounds in NCI-H460 cells. Conjugate 4' represents a new chemotype with potential applications in the treatment of chemoresistant tumors.

The role of topoisomerases and RNA transcription in the action of the antitumour benzonaphthyridine derivative SN 28049

PURPOSE

SN 28049 (N-[2-(dimethylamino)ethyl]-2,6-dimethyl-1-oxo-1,2-dihydrobenzo[b]-1,6-naphthyridine-4-carboxamide) is a DNA intercalating drug that binds selectively to GC-rich DNA and shows curative activity against the Colon 38 adenocarcinoma in mice. We wished to investigate the roles of topoisomerase (topo) I, topo II and RNA transcription in the action of SN 28049.

METHODS

We used clonogenic assays to study the cytotoxicity of SN 28049; RNA interference and enzyme assays to examine the role of topo I in SN 28049 action; 3H uridine incorporation and reporter assays to study its effects on transcription; and RT-PCR to examine its ability to reduce endogenous h-TERT expression.

RESULTS

In clonogenic assays, SN 28049 showed a biphasic cytotoxic dose response curve in H460 cells typical of acridine derivatives such as N-[2-(dimethylamino)ethyl]acridine-4-carboxamide (DACA) although it was approximately 16-fold more potent. Down-regulation of topo IIalpha in HTETOP cells reduced the cytotoxicity of SN 28049, establishing its action as a topo IIalpha poison. Surprisingly, down-regulation of topo I in H460 cells by RNA interference sensitised them to the actions of SN 28049 and other topo II poisons. SN 28049 also inhibited topo I-mediated relaxation of supercoiled plasmid DNA. SN 28049 was also an inhibitor of transcription in HEK293 cells and was more potent at reducing luciferase expression from a GC-rich SP-1 binding promoter than from a non-GC-rich AP-1 binding promoter. The drug also reduced luciferase reporter gene expression driven by the SP-1-binding survivin promoter as well as reducing endogenous h-TERT expression in HEK293 cells whose promoter also contains SP-1 binding sites.

CONCLUSION

We conclude that SN 28049 has a complex action that may involve poisoning of topo IIalpha, suppression of topo I and inhibition of gene transcription from promoters with SP-1 sites. These actions may contribute to the promising experimental solid tumour anticancer activity of SN 28049.

3,4-Dihydro-1H-[1,3]oxazino[4,5-c]acridines as a new family of cytotoxic drugs

A series of [1,3]oxazino fused acridines has been prepared as precursors of cytotoxic 3-amino-4-hydroxymethylacridine 2. Their cytotoxic activity has been evaluated against HT29 colon carcinoma cell line and was shown to be dependent on the nature of the substituent located on position 2 of the oxazine ring. Additionally, the nitrophenyl derivative 3f is activated by nitroreductase, indicating its potency as prodrug for either gene-directed or antibody-directed enzyme prodrug therapies.

Synthesis and cytotoxic activities of 8-alkyl or 8-aryl-8,9-dihydro-7H-isoindolo[5,6-g]quinoxaline-7,9-diones

A series of 8-alkyl- and 8-aryl-8,9-dihydro-7H-isoindolo[5,6- g]quinoxaline-7,9-diones were synthesized using sultine chemistry as a key step in good yield. These compounds were evaluated for their in vitro cytotoxicity against six human cancer cell lines (HCT15, SK-OV-3, A549, SNB19, MCF7 and MCF7/ADR).

Second-line treatment for advanced non-small cell lung cancer: A systematic review

BACKGROUND

Among advanced non-small cell lung cancer (NSCLC) patients, most will resist or relapse after first-line chemotherapy. As a result, second-line therapy has been a major focus for clinical research.

MATERIALS AND METHODS

A systematic review was carried out from 1996 to February 2005.

RESULTS

Second-line chemotherapy provides pre-treated NSCLC patients with a clear survival advantage. Docetaxel 75 mg/m(2) every 3 weeks is the present standard second-line chemotherapy. Despite promising results regarding efficacy and toxicity in phase III studies, a docetaxel weekly schedule could not be recommended. Pemetrexed recently emerged as an alternative with similar efficacy and less toxicity. Although the combination of two drugs was not associated with a survival benefit when compared with single-agent chemotherapy, such regimens induced a dramatic increase in toxicities and therefore mono-chemotherapy remains the standard as second-line therapy. Finally, few new agents were reported with better results than those used previously and clinical research on second-line therapy currently focuses on combinations with targeted therapies.

CONCLUSION

Second-line chemotherapy offers NSCLC patients a small but significant survival improvement. However, this field of clinical research needs further investigations in order to answer certain remaining questions especially concerning targeted therapies.

Synthesis andin vitro cytotoxicity of 1,3-dioxoindan-2-carboxylic acid arylamides

A series of 1,3-dioxoindan-2-carboxylic acid arylamides were synthesized and evaluated for in vitro cytotoxicity against four human cancer cell lines (HOP62, SK-OV-3, MD-MB-468 and T-47D). The most active was compound 3e (1.2 microM against SK-OV-3 cell line) bearing a 4-methyl substituent.

Phase II study of XR5000 (DACA), an inhibitor of topoisomerase I and II, administered as a 120-h infusion in patients with advanced ovarian cancer

BACKGROUND

XR5000 is a tricyclic carboxamide-based cytotoxic agent that binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II. The aim of the present study was to evaluate the antitumoral activity and safety profile of XR5000 given as second-line chemotherapy in patients with ovarian cancer who had relapsed within 1 year after first-line chemotherapy with taxanes and platinum for advanced disease.

PATIENTS AND METHODS

Patients received XR5000 at the dose of 3010 mg/m(2) through a 120-h central venous infusion every 3 weeks. Toxicity was graded according to the Common Toxicity Criteria (CTC), version 2.0. An independent panel assessed response every two cycles according to the World Health Organization (WHO) criteria. Gehan's rule was used for sample size determination.

RESULTS

Sixteen patients were enrolled; one patient was ineligible because of prior melphalan single agent treatment. Eastern Cooperative Oncology Group (ECOG) performance status was 0 (eight patients), 1 (five patients), or 2 (two patients). The 15 eligible patients received 43 cycles of XR5000 (median 2, range 1-8). Hematological toxicity was mild with only one grade 3 anemia in one patient. Other drug-related toxicities never exceeded grade 3 and included fatigue (four patients), thrombosis (one patient), nausea (one patient), stomatitis (one patient) as well as dyspnea/cough (one patient). One patient who had refused further therapy and controls after the first cycle was not assessable for response evaluation. No objective responses were observed. Four patients experienced stable disease and 10 patients progressive disease. The median time to progression was 42 days (CI 95% 40; 54).

CONCLUSIONS

The complete lack of any objective response does not justify further evaluation of XR5000 in patients with advanced ovarian cancer using this dose and schedule, although the therapy was generally well tolerated.