ABSTRACT
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.
Subject(s)
Antineoplastic Agents/pharmacology , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Apoptosis/drug effects , Camptothecin/analogs & derivatives , Cell Cycle Checkpoints/drug effects , Colonic Neoplasms/drug therapy , Curcumin/pharmacology , Endoplasmic Reticulum Stress/drug effects , Calcium/metabolism , Camptothecin/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Drug Synergism , Drug Therapy, Combination , Endoplasmic Reticulum Chaperone BiP , Heat-Shock Proteins/metabolism , Humans , Irinotecan , RNA Interference , RNA, Small Interfering/genetics , Reactive Oxygen Species/metabolism , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolismABSTRACT
The polymorphism in a fragment within the coding region of the inhibin a subunit ( INHA ) gene was studied in 323 heads of Matou, Nubi, Boar and Haimen goats by PCR-SSCP, PCR-RFLP and sequencing. A new mutation G284A (Accession number: L28815) was identified, which could be detected by Hae digestion of a PCR product spanning this site. Hae PCR-RFLP analysis indicated that allele G was dominant. Association studies indicated that the effect of INHA genotypes on litter size was greatest for GG, followed by AG and AA genotypes. Thus, INHA may be a major gene controlling the prolificacy of goat, and allele G is positively correlated with litter size.