cytochrome-c-t and isoliquiritigenin

A large body of research has demonstrated a synergistic anticancer effect between docosahexaenoic acid (DHA) and standard chemotherapy regimens against colorectal cancer (CRC). In this study, we investigated the chemotherapeutic potential of cotreatment with DHA and isoliquiritigenin (ISL) against CRC HCT-116 cells. Apoptosis was confirmed by Annexin V/PI staining and expression of apoptosis-associated proteins. The synergistic effect of DHA and ISL combination on apoptosis was detected using combination index approaches. Flow cytometry was carried out using fluorescent probes to measure the production of reactive oxygen species (ROS). DHA and ISL in combination synergistically enhanced the decrease in cell viability versus the compounds used alone. Moreover, we demonstrated that the synergistic anti-CRC activity of cotreatment with these two compounds was achieved by inducing the apoptosis caspase-dependently mediated through augmented ROS generation followed by increased Fas ligand mRNA expression and cytochrome c release. Our data also demonstrated that cotreating with DHA and ISL strongly upregulated the phosphorylation of ERK and JNK, which are functionally associated with ROS induced by the two compounds in combination. Interestingly, further study revealed that inhibiting ERK phosphorylation strongly enhanced Fas ligand mRNA expression and the combination of the two compounds induced stronger cytotoxicity, whereas inhibiting JNK phosphorylation significantly reduced the apoptotic signals mediated by cotreatment with these two compounds. Excessive ROS-induced JNK activation and cytochrome c release from mitochondria played a key role in the synergistic anticancer activity of CRC cells by cotreating with DHA and ISL.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Chalcones; Colorectal Neoplasms; Cytochromes c; Docosahexaenoic Acids; Drug Synergism; Humans; MAP Kinase Kinase 4; Reactive Oxygen Species

Flavonoids have antitumoral properties and may be attractive candidates as anticancer therapy. Isoliquiritigenin which is a constituent of licorice (Glycyrrhiza inflata), a plant commonly used in traditional Uyghur medicine in Xinjiang, China, was studied for antiproliferative and apoptotic activity in human cervical cancer cells, Ca Ski, SiHa, HeLa, and C-33A. Its molecular mechanism of action was specifically examined in Ca Ski cells. Isoliquiritigenin decreased cell viability, induced cell accumulation in G2/M and morphological and biochemical features of apoptosis in the four cancer cell lines. In Ca Ski cells, isoliquiritigenin led to a downregulation of HPV16 E6 expression associated with an increase of p53 and p21 levels, enhanced expression of Bax and decreased expression of Bcl-2 and Bid proform triggering dissipation of the mitochondrial membrane potential, released cytochrome c to the cytosol followed by activation of caspase cascade with cleavage of caspase-9, caspase-3, and PARP. Caspase-8 was also cleaved. Moreover treatment with a pan-caspase inhibitor prevented apoptosis. As Ca Ski cells are representative of carcinoma naturally occurring in the cervix, our results suggest a potential benefit of isoliquiritigenin for cervical cancer prevention and treatment.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; BH3 Interacting Domain Death Agonist Protein; Caspase Inhibitors; Caspases; Cell Line, Tumor; Chalcones; Cytochromes c; Down-Regulation; Drugs, Chinese Herbal; Female; Glycyrrhiza; HeLa Cells; Humans; Membrane Potential, Mitochondrial; Mitochondria; Oncogene Proteins, Viral; Phytotherapy; Proto-Oncogene Proteins c-bcl-2; Repressor Proteins; Tumor Suppressor Protein p53; Uterine Cervical Neoplasms

Isoliquiritigenin (ISL), a simple chalcone derivative, 4,2',4'-trihydroxychalcone, found in licorice, shallot and bean sprouts, has been reported to have chemoprotective effects. To examine the effects of ISL on the growth of prostate cancer cells, we cultured MAT-LyLu (MLL) rat and DU145 human prostate cancer cells with various concentrations (0-20 micromol/L) of ISL. Treatment of the cells with increasing concentrations of ISL led to dose-dependent decreases in the viable cell numbers in both DU145 and MLL cells (P<.05). Hoechst 33258 dye staining of condensed nuclei and annexin V binding to surface phosphatidylserine revealed increased numbers of apoptotic cells after ISL treatment. Western blot analysis revealed that ISL increased the levels of membrane-bound Fas ligand (FasL), Fas, cleaved casapse-8, truncated Bid (tBid), Bax and Bad in DU145 cells (P<.05). Isoliquiritigenin increased the percentage of cells with depolarized mitochondrial membranes, in a concentration-dependent manner (P<.05). Isoliquiritigenin induced the release of cytochrome c and Smac/Diablo from the mitochondria into the cytoplasm (P<.05). Isoliquiritigenin dose-dependently increased the levels of cleaved caspase-9, caspase-7, caspase-3 and poly(ADP-ribose) polymerase (P<.05). The present results indicate that ISL inhibits prostate cancer cell growth by the induction of apoptosis, which is mediated through mitochondrial events, which are associated with an evident disruption of the mitochondrial membrane potential, and the release of cytochrome c and Smac/Diablo, and the activation of caspase-9.

Topics: Animals; Apoptosis; Blotting, Western; Caspases; Cell Division; Cell Line, Tumor; Chalcone; Chalcones; Cytochromes c; Enzyme Activation; Fas Ligand Protein; fas Receptor; Flow Cytometry; Humans; Male; Membrane Glycoproteins; Membrane Potentials; Mitochondrial Membranes; Poly(ADP-ribose) Polymerases; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Rats; Tumor Necrosis Factors