1.Inhibition of phospholipase D2 induces autophagy in colorectal cancer cells.
Won Chan HWANG ; Mi Kyoung KIM ; Ju Hyun SONG ; Kang Yell CHOI ; Do Sik MIN
Experimental & Molecular Medicine 2014;46(12):e124-
Autophagy is a conserved lysosomal self-digestion process used for the breakdown of long-lived proteins and damaged organelles, and it is associated with a number of pathological processes, including cancer. Phospholipase D (PLD) isozymes are dysregulated in various cancers. Recently, we reported that PLD1 is a new regulator of autophagy and is a potential target for cancer therapy. Here, we investigated whether PLD2 is involved in the regulation of autophagy. A PLD2-specific inhibitor and siRNA directed against PLD2 were used to treat HT29 and HCT116 colorectal cancer cells, and both inhibition and genetic knockdown of PLD2 in these cells significantly induced autophagy, as demonstrated by the visualization of light chain 3 (LC3) puncta and autophagic vacuoles as well as by determining the LC3-II protein level. Furthermore, PLD2 inhibition promoted autophagic flux via the canonical Atg5-, Atg7- and AMPK-Ulk1-mediated pathways. Taken together, these results suggest that PLD2 might have a role in autophagy and that its inhibition might provide a new therapeutic basis for targeting autophagy.
Autophagy/*drug effects
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Cell Line, Tumor
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Colorectal Neoplasms/enzymology/*genetics/*therapy
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Genetic Therapy
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HCT116 Cells
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Humans
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Phospholipase D/*antagonists & inhibitors/*genetics/metabolism
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Quinolines/*pharmacology
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*RNA Interference
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RNA, Small Interfering/genetics/pharmacology
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Signal Transduction/drug effects
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Spiro Compounds/*pharmacology
2.Effects of Jianpi Jiedu Recipe on reversion of P-glycoprotein-mediated multidrug resistance through COX-2 pathway in colorectal cancer.
Hua SUI ; Hui-rong ZHU ; Jie WU ; Alexander Yu NIKITIN ; Jian-feng CAI ; Zhong-ze FAN ; Qi LI
Chinese journal of integrative medicine 2014;20(8):610-617
OBJECTIVETo evaluate the underlying mechanism of Jianpi Jiedu Recipe (, JJR) in the reversion of multidrug resistance concerning colorectal cancer in vitro and in vivo.
METHODSMice were treated orally with JJR at a daily 4.25 g/(kg·day) or injected with vinblastine (VCR) 2.5 mg/(kg·day) for 3 weeks after having been inoculated with HCT8/V cells; tumor tissues were assayed by hematoxylin and eosin staining. Firstly, the effects of JJR on the expression of cyclooxygenase-2 (COX-2) were tested by real-time polymerase chain reaction (PCR) technique and COX-2 gene silenced by siRNA. Secondly, the variation of intracellular concentration of oxaliplatin (L-OHP) was evaluated by the inductively coupled plasma mass spectroscopy (ICPMS) in HCT8/V and its COX-2 siRNA cells; the concentration of JJR combined with chemotherapeutic drugs and the reverse effect of multidrug resistance (MDR) in HCT8/V cells was evaluated by the MTT assay. Thirdly, real-time quantitative PCR and Western blot analysis were used to detect the multidrug resistance gene 1 (MDR1) mRNA and P-gp expression.
RESULTSJJR had an inhibitory effect on the growth of tumors in vivo, and it, in combination with chemotherapeutic drugs, could reverse the drug-resistance of HCT8/V cells and increase the sensitivity of HCT8/V cells to VCR, DDP, 5-Fu, and THP. ICP-MS results showed that JJR could increase the concentration of drugs in HCT8/V cells (P<0.01). Furthermore, it was shown that JJR could reverse drug resistance of colorectal cancer cells by decreasing MDR1 expression and P-gp level via downregulation of COX-2, which has been represented as one of the major mechanisms that contributes to the MDR phenotype (P<0.01).
CONCLUSIONJJR reversed multidrug resistance and enhanced the sensitivity to chemotherapy, which could be attributed to the down-regulation of COX-2 in MDR1/P-gp-mediated MDR colorectal cancer after chemotherapy.
ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Animals ; Cell Line, Tumor ; Cell Proliferation ; Colorectal Neoplasms ; drug therapy ; enzymology ; pathology ; Cyclooxygenase 2 ; genetics ; metabolism ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Green Fluorescent Proteins ; metabolism ; Humans ; Intracellular Space ; metabolism ; Mice, Inbred BALB C ; Organoplatinum Compounds ; metabolism ; RNA, Small Interfering ; metabolism ; Signal Transduction ; drug effects ; Vinblastine ; pharmacology ; therapeutic use ; Xenograft Model Antitumor Assays