ABSTRACT
AIM: To investigate whether microRNA (miR)-34a mediates oxaliplatin (OXA) resistance of colorectal cancer (CRC) cells by inhibiting macroautophagy via the transforming growth factor (TGF)-ß/Smad4 pathway. METHODS: miR-34a expression levels were detected in CRC tissues and CRC cell lines by quantitative real-time polymerase chain reaction. Computational search, functional luciferase assay and western blotting were used to demonstrate the downstream target of miR-34a in CRC cells. Cell viability was measured with Cell Counting Kit-8. Apoptosis and macroautophagy of CRC cells were analyzed by flow cytometry and transmission electron microscopy, and expression of beclin I and LC3-II was detected by western blotting. RESULTS: Expression of miR-34a was significantly reduced while expression of TGF-ß and Smad4 was increased in CRC patients treated with OXA-based chemotherapy. OXA treatment also resulted in decreased miR-34a levels and increased TGF-ß and Smad4 levels in both parental cells and the OXA-resistant CRC cells. Activation of macroautophagy contributed to OXA resistance in CRC cells. Expression levels of Smad4 and miR-34a in CRC patients had a significant inverse correlation and overexpressing miR-34a inhibited macroautophagy activation by directly targeting Smad4 through the TGF-ß/Smad4 pathway. OXA-induced downregulation of miR-34a and increased drug resistance by activating macroautophagy in CRC cells. CONCLUSION: miR-34a mediates OXA resistance of CRC by inhibiting macroautophagy via the TGF-ß/Smad4 pathway.
Subject(s)
Antineoplastic Agents/therapeutic use , Autophagy/genetics , Colorectal Neoplasms/drug therapy , Drug Resistance, Neoplasm/genetics , MicroRNAs/metabolism , Organoplatinum Compounds/therapeutic use , Smad4 Protein/metabolism , Transforming Growth Factor beta/metabolism , Aged , Antineoplastic Agents/administration & dosage , Apoptosis/drug effects , Beclin-1/metabolism , Colorectal Neoplasms/blood , Colorectal Neoplasms/genetics , Colorectal Neoplasms/physiopathology , Flow Cytometry , HT29 Cells , Humans , MicroRNAs/drug effects , Microscopy, Electron, Transmission , Microtubule-Associated Proteins/metabolism , Middle Aged , Organoplatinum Compounds/administration & dosage , Oxaliplatin , Real-Time Polymerase Chain Reaction , Signal TransductionABSTRACT
OBJECTIVE: To observe the incidence of heparin-induced thrombocytopenia (HIT) in patients received unfractionated heparin (UFH) treatment, and explore the feasibility of monitoring HIT by platelet counts, as well as the significance of HIT-antibody test in HIT diagnosis. METHODS: 145 patients received UFH treatment in Vascular Surgery Department were studied. Before and after the UFH treatment, platelet counts, HIT-antibody ELISA test and heparin-induced platelet aggregation (HIPA) were tested. RESULTS: Among the 145 patients, thrombocytopenia occurred in 40 (27.6%) cases, HIT-antibody ELISA test positive in 59 (40.7%) cases, HIPA test positive in 26 (17.9%) cases. The HIT was diagnosed in 24 (16.5%) cases, and heparin-induced thrombocytopenia and thrombosis (HITTS) occurred in 5 (3.4% in all cases, and 20.8% in HIT patients). In HIT patients, 15 patients (62.5%) were thrombocytopenia, HIT-antibody positive and HIPA test positive. Platelet counts in all of the 24 patients recovered to normal or level before UFH treatment in 3-6 days after heparin withdrawal therapy. CONCLUSION: HIT can be early diagnosed by monitoring platelet counts, HIT-antibody ELISA test and HIPA test. Withdrawal of heparin therapy in time and use of alternative anticoagulant, HITTS rate might be expected to decline further.
