Effects, in an in-vivo model system, of 1,2,3,4-tetrahydroisoquinoline on glioma

Crocus sativus L. Causes a Non Apoptotic Calpain Dependent Death in C6 Rat Glioma Cells, Exhibiting a Synergistic Effect with Temozolomide

Crocus sativus L., a dietary herb, has been used for various diseases including cancer. This is an in vitro study investigating the antineoplastic effect of the extract of the plant against C6 glioma rat cell line. The mechanism of cellular death and the synergistic effect of the extract with the alkylating agent temozolomide (TMZ) were investigated. Cellular viability was examined in various concentrations of the extract alone or in combination with TMZ. Apoptosis was determined with flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and autophagy by western blotting of the light chain 3 (LC3)-II. Cellular viability was reduced after exposure to the extract with half maximal inhibition concentration at 3 mg/ml. Flow cytometry and TUNEL assay suggested that the extract does not induce apoptosis. Moreover, their combination increased the ratio dead/apoptotic cells 10-fold (P < 0.001). LC3-II protein levels reduced after Crocus extract while this effect was reversed when the calpain inhibitor MDL28170 was added, suggesting a calpain-dependent death possibly through autophagy. We concluded that the extract of Crocus increases dead cell number after 48 h of exposure. Our results suggest that the cell undergoes calpain-dependent programmed cell death while co-exposure to Crocus extract and TMZ enhances the antineoplastic effect of the latter.

Tetrahydroisoquinolines in therapeutics: a patent review (2010-2015)

INTRODUCTION

1,2,3,4-Tetrahydroisoquinoline (THIQ) is one of the 'privileged scaffolds', commonly found in nature. Initially, this class of compounds was known for its neurotoxicity. Later on, 1-methyl-1,2,3,4-tetrahydroisoquinoline was proved as an endogeneous Parkinsonism-preventing agent in mammals. The fused THIQs have been studied for their role as anticancer antibiotics. The US FDA approval of the trabectedin for the treatment of soft tissue sarcomas, is a milestone in the anticancer drug discovery. Areas covered: This review covers the patents on various therapeutic activities of the THIQ derivatives in the years between 2010 and 2015. Patents were collected using a thorough search of Espacenet and WIPO databases. The therapeutic areas covered include cancer, malaria, central nervous system (CNS), cardiovascular, metabolic disorders, and so on. This also includes several patents on specific THIQs of clinical importance. Expert opinion: A large number of the THIQ derivatives have been synthesised for various therapeutic activities, with noticeable success in the area of drug discovery for cancer and CNS. They may also prove to be promising candidates for various infectious diseases, such as malaria, tuberculosis, HIV-infection, HSV-infection, leishmaniasis, etc. They can also be developed as novel class of drugs for various therapeutic activities with unique mechanism of action.

New substituted 4H-chromenes as anticancer agents

As a continuation of our efforts to discover and develop small molecules as anticancer agents, we identified GRI-394837 as an initial hit from similarity search on RGD and its analogs. Based on GRI-394837, we designed and synthesized a focused set of novel chromenes (4a-e) in a single step using microwave method. All five compounds showed activity in the nanomolar range (IC(50): 7.4-640 nM) in two melanoma, three prostate and four glioma cancer cell lines. The chromene 4e is active against all the cell lines and particularly against the A172 human glioma cell line (IC(50): 7.4 nM). Interestingly, in vitro tubulin polymerization assay shows 4e to be a weak tubulin polymerization inhibitor but it shows very strong cytotoxicity in cellular assays, therefore there must be additional unknown mechanism(s) for the anticancer activity. Additionally, the strong antiproliferative activity was verified by one of the selected chromene (4a) by the NCI 60 cell line screen. These results strongly suggest that the novel chromenes could be further developed as a potential therapeutic agent for a variety of aggressive cancers.