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Although initially effective against metastatic colorectal cancer (CRC), irinotecan-based chemotherapy leads to resistance and adverse toxicity. Curcumin is well known for its anti-cancer effects in many cancers, including CRC. Here, we describe reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress as important mechanisms by which curcumin enhances irinotecan's effects on CRC cells. CRC cell lines were treated with curcumin and/or irinotecan for 24 h, and then evaluated using cell proliferation assays, cell apoptosis assays, cell cycle analysis, intracellular Ca2+ measurements, ROS measurements and immunoblotting for key ER stress-related proteins. We found that cell viability was inhibited and apoptosis was increased, accompanied by ROS generation and ER stress activation in CRC cells treated with curcumin alone or in combination with irinotecan. Blocking ROS production attenuated the expression of two markers of ER stress: binding of immunoglobulin protein (BIP) and CCAAT/enhancer-binding protein homologous protein (CHOP). Blocking CHOP expression using RNA interference also inhibited ROS generation. These results demonstrated that curcumin could enhance the effects of irinotecan on CRC cells by inhibiting cell viability and inducing cell cycle arrest and apoptosis, and that these effects may be mediated, in part, by ROS generation and activation of the ER stress pathway.

Objective: We wish to implement a proteomics-based approach to pick and identify the proteins associated with curcumin enhancing efficacy of irinotecan inducing apoptosis of colorectal cancer LOVO cells, and further explore their synergy mechanism by bioinformatics., Methods: A colorectal cancer cell line (LOVO cell) treated by curcumin combined with irinotecan in different ways respectively was used as our comparative model. Protein spots were analyzed through MALDI-TOF/TOF. The location and function of differential protein spots were analyzed through UniProt database. Protein-protein interactions were examined through String software., Results: A total of 54 protein spots differentially expressed with 1.5-fold difference were picked, 11 of which were repeated. They mainly were involved in intracellular calcium pathways, cellular respiratory chain pathway and intracellular redox reaction pathways of LOVO cell. According to the function of various protein points, combining with varying curves of protein points in each treatment groups, we selected five interesting protein spots, 4 of which exists Protein-protein interactions, and they were close to the formation and reduction of disulfides in intracellular endoplasmic reticulum (ER)., Conclusion: We selected preliminary but comprehensive data about differential expression protein spots of LOVO cell. Among these, the five interesting differential expression protein spots identified in this study may provide new insight into LOVO cell therapeutic biomarkers. Curcumin may suppress GSTM5 expression to enhance the lethal effect of irinotecan on LOVO cells, and maybe their combination via the affection of PDI and PRDX4 to disturb the formation and reduction of disulfides results in inducing apoptosis of LOVO cell.

Previous studies have demonstrated that Licochalcone A possesses anti-inflammatory, anticancer, anti-bacterial, anti-malarial and anti-parasitic activities. In the present study the potential anticancer effects of Licochalcone A on MCF-7 cells were investigated. Licochalcone A significantly decreased cell viability and promoted autophagy and apoptosis, as demonstrated by an MTT assay, acridine orange staining and Annexin V-fluorescein isothiocyanate staining, respectively. Western blot analyses demonstrated that Licochalcone A treatment activated the LC3-II signaling pathway while suppressing the phosphoinositide 3-kinase (PI3K)/RAC-α serine-threonine-protein kinase (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. In addition, Licochalcone A significantly increased caspase-3 activity and significantly decreased B-cell lymphoma-2 expression. The results from the present study indicate that Licochalcone A inhibits PI3K/Akt/mTOR activation, and promotes autophagy and apoptosis in MCF-7 cells. [ABSTRACT FROM AUTHOR]

Abstract: Insulin-like peptide 3 (INSL3) is a peptide hormone belonging to the insulin/relaxin superfamily, which mediates testes descent in the male fetus, and suppresses male germ cell apoptosis and promotes oocyte maturation in adults by activating the leucine-rich repeat-containing G-protein coupled receptor RXFP2. In a previous work, we prepared mature two-chain INSL3 by recombinant expression of a designed single-chain precursor in Escherichia coli and subsequent in vitro maturation. To establish a convenient high throughput receptor-binding assay for screening novel RXFP2 agonists or antagonists, in the present study we designed and recombinantly prepared a fully active easily-labeled INSL3 analog. Due to presence of a single primary amine moiety, the easily-labeled analog was conveniently mono-labeled by a DTPA/Eu3+-moiety at the A-chain N-terminus through reacting with excess modification reagent in a simple one-step procedure. The DTPA/Eu3+-labeled INSL3 analog bound receptor RXFP2 with high affinity and low non-specific binding. Using this non-radioactive tracer, we established a high throughput cell-based receptor-binding assay for screening of novel RXFP2 agonists or antagonists in future studies. [Copyright &y& Elsevier]

Background: This study aims to clarify the underlying mechanism for the tumor suppressive function of lnc TUSC7 in chemotherapy resistance of esophageal squamous cell carcinoma (ESCC). Methods: TUSC7, miR-224 and DESC1 expressions in ESCC tissues and cells were detected by qRT-PCR. Protein level of DESC1, EGFR and p-AKT were observed by Western blot. Overall survival was calculated using the Kaplan-Meier method. Dual-luciferase reporter gene assay and RIP assay were used to comfirm TUSC7 binding to miR-224, and miR-224 binding to DESC1. Cell proliferation, apoptosis, and colony formation was detected by MTT, Flow Cytometry and Colony formation assays. Results: TUSC7 was downregulated in ESCC tissues and cells, and low TUSC7 indicated worse overall survival. The analysis of bioinformatics softwares showed that TUSC7 specifically bound to miR-224, and we proved miR-224 was upregulated in ESCC and negatively correlated with TUSC7 expression. Overexpression of TUSC7/inhibition of miR-224 suppressed cell proliferation, colony formation and chemotherapy resistance of ESCC cells, and promoted cell apoptosis. In addition, we confirmed that miR-224 specifically bound to DESC1, and negatively correlated with DESC1. TUSC7 suppressed the proliferation and chemotherapy resistance of ESCC cells by increasing DESC1 expression via inhibiting miR-224. We also confirmed DESC1 inhibited chemotherapy resistance of ESCC cells via EGFR/AKT. Finally, in vivo experiments demonstrated that overexpression of TUSC7 decreased tumor growth and chemotherapy resistance. Conclusion: These findings suggested TUSC7 suppressed chemotherapy resistance of ESCC by downregulating miR-224 to modulate DESC1/EGFR/AKT pathway. [ABSTRACT FROM AUTHOR]