Chemotherapeutic and Antiproliferative Effect of Purified Protein from Marine Catfish Tachysurus Dussumieri on Human Colon Cancer Cell Line

The present study aimed to investigate the purified protein from the epidermal mucus of marine catfish Tachysurus dussumieri on the human colon cancer cell line. The bioactive protein was purified with the Anion exchange chromatography and the collected fractions were then tested to assess cell viability in HT 29 cells through the MTT assay. The most responding active purified protein fraction (PPF III) was characterized with the MALDI-TOF/MS it shared a similar homology and sequence with 90% of antimicrobial peptides from external secretions of amphibians. Typical morphological changes of apoptotic cells, including cell shrinkage and detachment, DNA damage, and nuclear condensation were observed after the treatment of bioactive protein. PPF III triggered ROS, increasing the LDH activity, disruption of mitochondrial membrane potential, and upregulation of Cleaved caspase 3/9, Cytochrome-c, Bax, and downregulation of Bcl-2 protein and gene expression on HT 29 cells.

Repositioning of simvastatin for diabetic colon cancer: role of CDK4 inhibition and apoptosis

There is increased risk of colon cancer in both men and women having diabetes. The objective of the study was to evaluate the role of simvastatin in colon cancer associated with type 2 diabetes mellitus. Diabetes was induced by administering high fat diet with low dose streptozotocin model. 1,2 dimethylhydrazine (25 mg/kg, sc) was used for colon cancer induction. MTT assay, scratch assay, clonogenic assay and annexin V-FITC assay using flow cytometry were performed on HCT-15 cell line. Simvastatin controlled diabetes and colon cancer in animal models and reduced mRNA expression of CDK4 in colon tissues. In vitro studies revealed that simvastatin showed a decrease in cell viability and produced dose dependent decrease in clone formation. There was decrease in the rate of migration with increase in concentration of simvastatin in scratch assay. Moreover, simvastatin induced apoptosis as depicted from annexin V-FITC assay using flow cytometry as well as that revealed by tunnel assay. Our data suggest that simvastatin exhibits protective role in colon cancer associated with diabetes mellitus and acts possibly via down regulation of CDK4 and induction of apoptosis and hence can be considered for repositioning in diabetic colon cancer.

Cytotoxic effect of Cyperus rotundus rhizome extract on human cancer cell lines

The wild weed Cyperus rotundus is commonly used as traditional medicine in different parts of the world. Sequential extraction of C. rotundus rhizome with solvents of different polarity namely hexane, chloroform, ethyl acetate, methanol and water were prepared and the free radical scavenging activity was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Based on high antioxidant activity of methanolic extract of C. rotundus rhizome (MRCr) was further investigated for its cytotoxic effect on different human cancer cell lines-breast (MCF-7), cervical (HeLa), liver (Hep G2), prostate (PC-3), colorectal (HT-29) and normal cell line (MCF-12A) by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay evaluated as 50% inhibition of growth (IC₅₀). Apoptosis cells were analysed by flow cytometry stained with annexin V-Fluorescein isothiocyanate conjugate (AF) and propidium iodide (PI). The cellular and nuclear changes were examined under light and fluorescent microscope using 4', 6' diamino-2-phenylindole (DAPI) stain, dual stains of AF/PI and acridine orange/ethidium bromide (AO/EB). The cytotoxic effects on the tested cancer cell lines ranged from 4.52±0.57 to 9.85±0.68μgml^-1. The migration assay was showed the inhibitory effect with MRCr. The MRCr showed significant anticancer activity against all the tested cancer cell lines and also protected the non-cancer cells. The anticancer activity suggests further elucidation for the formulation of natural pharmaceutical products in the treatment of cancer.

Investigation of the mechanism and apoptotic pathway induced by 4β cinnamido linked podophyllotoxins against human lung cancer cells A549

Apoptosis is essential for normal development and the maintenance of homeostasis. It plays a necessary role to protect against carcinogenesis by eliminating damaged cells. Many studies have demonstrated that the dysregulation of apoptosis results in cancer and this provides an approach to develop therapeutic agents via inducing apoptosis. In our previous studies 4β-cinnamido linked podophyllotoxin conjugates were synthesized and evaluated for their cytotoxic activity in a panel of five human cancer cell lines and the new molecules like 17a and 17f were considered as potential leads. The cytotoxic activity was comparable to etoposide. These observations prompted us to investigate the mechanism underplaying the cytotoxic activity and apoptotic pathway induced by these compounds in human lung cancer cells A459. The results of the present study revealed that these compounds exhibited DNA topoisomerase IIα inhibition and induced mitochondrial mediated apoptosis. It was further confirmed by Mitochondrial membrane potential, Cytochrome c release, cleavage of poly (ADP-ribose) polymerase (PARP), Reactive oxygen species (ROS) generation, regulation of antiapoptotic protein Bcl-2 and pro apoptotic protein Bax studied by Western blot analysis. Annexin V-FITC assay also suggested that these compounds induced cell death by apoptosis. Pretreatment with N-acetyl-L-cysteine (NAC) prevented the generation of ROS. Further, pretreatment with NAC significantly inhibited 17a and 17f induced apoptosis, suggesting that ROS are the key mediators for 17a and 17f induced apoptosis. These data indicate that these compounds might induce apoptosis in A549 cells through a ROS mediated mitochondrial dysfunction pathway. Moreover, these compounds did not significantly inhibit the noncancerous human embryonic kidney cells, HEK-293. Docking studies also elucidate the potential of these molecules to bind to the DNA topoisomerase II. Podophyllotoxin analogs were investigated for their mechanism and apoptotic pathway against lung cancer cell line, A549. These podophyllotoxin analogs inhibited DNA topoisomerase IIα and induced mitochondrial mediated apoptosis in lung cancer cell line, A549. Western blot analysis suggested that these compounds inhibited the DNA topoisomerase IIα. Studies like, Measurement of mitochondrial membrane potential (∆Ψm), Generation of intracellular reactive oxygen species (ROS) and Annexin V-FITC assay suggested that these compounds induced mitochondrial mediated apoptosis. Pretreatment with N-acetyl-L-cysteine (NAC) suggested that ROS plays a role in 17a and 17f induced apoptosis. Further the apoptotic effect of these compounds was confirmed by western blot analysis of pro apoptotic protein Bax and antiapoptotic protein Bcl-2, Cytochrome c release and cleavage of poly (ADP-ribose) polymerase (PARP). Moreover, these compounds did not significantly inhibit the noncancerous human embryonic kidney cells, HEK-293.