Objective: To observe the platinum drugs resistance effect of N-acetyltransferase 10 (NAT10) overexpression in breast cancer cell line and elucidate the underlining mechanisms. Methods: The experiment was divided into wild-type (MCF-7 wild-type cells without any treatment) group, NAT10 overexpression group (H-NAT10 plasmid transfected into MCF-7 cells) and NAT10 knockdown group (SH-NAT10 plasmid transfected into MCF-7 cells). The invasion was detected by Transwell array, the interaction between NAT10 and PARP1 was detected by co-immunoprecipitation. The impact of NAT10 overexpression or knockdown on the acetylation level of PARP1 and its half-life was also determined. Immunostaining and IP array were used to detect the recruitment of DNA damage repair protein by acetylated PARP1. Flow cytometry was used to detect the cell apoptosis. Results: Transwell invasion assay showed that the number of cell invasion was 483.00±46.90 in the NAT10 overexpression group, 469.00±40.50 in the NAT10 knockdown group, and 445.00±35.50 in the MCF-7 wild-type cells, and the differences were not statistically significant (P>0.05). In the presence of 10 μmol/L oxaliplatin, the number of cell invasion was 502.00±45.60 in the NAT10 overexpression group and 105.00±20.50 in the NAT10 knockdown group, both statistically significant (P<0.05) compared with 219.00±31.50 in wild-type cells. In the presence of 10 μmol/L oxaliplatin, NAT10 overexpression enhanced the binding of PARP1 to NAT10 compared with wild-type cells, whereas the use of the NAT10 inhibitor Remodelin inhibited the mutual binding of the two. Overexpression of NAT10 induced PARP1 acetylation followed by increased PARP1 binding to XRCC1, and knockdown of NAT10 expression reduced PARP1 binding to XRCC1. Overexpression of NAT10 enhanced PARP1 binding to LIG3, while knockdown of NAT10 expression decreased PARP1 binding to LIG3. In 10 μmol/L oxaliplatin-treated cells, the γH2AX expression level was 0.38±0.02 in NAT10 overexpressing cells and 1.36±0.15 in NAT10 knockdown cells, both statistically significant (P<0.05) compared with 1.00±0.00 in wild-type cells. In 10 μmol/L oxaliplatin treated cells, the apoptosis rate was (6.54±0.68)% in the NAT10 overexpression group and (12.98±2.54)% in the NAT10 knockdown group, both of which were statistically significant (P<0.05) compared with (9.67±0.37)% in wild-type cells. Conclusion: NAT10 overexpression enhances the binding of NAT10 to PARP1 and promotes the acetylation of PARP1, which in turn prolongs the half-life of PARP1, thus enhancing PARP1 recruitment of DNA damage repair related proteins to the damage sites, promoting DNA damage repair and ultimately the survival of breast cancer cells.
Breast Neoplasms/enzymology* ; Cell Line, Tumor ; Drug Resistance, Neoplasm ; Female ; Humans ; MCF-7 Cells ; N-Terminal Acetyltransferases/metabolism* ; Organoplatinum Compounds/pharmacology* ; Oxaliplatin/pharmacology* ; X-ray Repair Cross Complementing Protein 1

OBJECTIVETo predict and identify the target gene of miR-145, and to explore the underlying mechanism of the inhibition of miR-145 on drug resistance to Oxaliplatin (L-OHP) in human colorectal cancer cells.

METHODSL-OHP-resistant human colorectal cancer cell line (HCT116/L-OHP) was established in vitro by exposing to increased concentrations of L-OHP in cell culture medium. MiR-145-mimics and its negative control (NC-miRNA) were transfected into HCT116/L-OHP cells using liposome to establish HCT116/L-OHPover-expressing miR-145 and HCT116/L-OHP. The target genes of miR-145 were predicted by bioinformatic analysis, and validated by dual luciferase activity assay. After determination of G protein coupled receptor 98(GPR98) as target gene, corresponding plasmids were constructed and transfected to establish HCT116/L-OHPover-expressing GPR98 and HCT116/L-OHP. HCT116/L-OHP cells over-expressing both GPR98 and miR-145 (HCT116/L-OHP) were acquired through modification of the binding sites of GPR98 cDNA with miR-145. CCK-8 assay was used to assess the proliferation (A value) and sensitivity to L-OHP (the lower the IC50, the stronger the sensitivity) in HCT116/L-OHP cells. Real-time quantitative PCR was used to measure the mRNA expression of miR-145 and GPR98. Western blot was used to examine the protein expression of GPR98 and drug-resistant associated protein, such as P-glycoprotein (gp), multiple drug-resistance protein 1(MRP1), cancer-inhibition gene PTEN.

RESULTSHCT116/L-OHP cell line was successfully established with ICof (42.34±1.05) mg/L and miR-145 mRNA expression of 0.27±0.04, which was higher than (9.81±0.95) mg/L (t=39.784, P=0.000) and lower than 1.00±0.09 (t=13.021, P=0.000) in HCT116 cells. Based on HCT116/L-OHP cells, HCT116/L-OHPcells were established successfully, with relative miR-145 expression of 10.01±1.05, which was higher than 1.06±0.14 in HCT116/L-OHPand 1.00±0.16 in HCT116/L-OHP (F=161.797, P=0.000). GPR98 was identified to be the target gene of miR-145. The relative mRNA and protein expressions of GPR98 in HCT116/L-OHPcells were 8.48±0.46 and 1.71±0.09, respectively, which were higher than those in HCT116/L-OHP(mRNA: 3.65±0.40, protein: 1.21±0.10) and HCT116/L-OHP (mRNA: 3.49±0.35, protein: 1.22±0.08; all P<0.05). The A value was 1.31±0.10, and the relative protein expressions of P-gp and MRP1 were 1.53±0.18 and 1.49±0.20 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP (A value: 0.82±0.08, relative protein expression: 1.00±0.06 and 1.21±0.13, all P<0.05). The A value was 0.89±0.08, and the relative protein expressions of P-gp and MRP were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP(A value: 0.20±0.05, relative protein expression: 0.20±0.07, 0.55±0.10, all P<0.05). The relative protein expression of PTEN in HCT116/L-OHPcells was 0.12±0.03, which was lower than 1.25±0.14 in HCT116/L-OHP cells(P<0.05). In addition, relative protein expressions of P-gp and MRP1 were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHPcells (0.20±0.07 and 0.55±0.10), while PTEN expression in HCT116/L-OHPcells was lower as compared to HCT116/L-OHPcells (1.41±0.16 vs. 1.98±0.13, P<0.05).

CONCLUSIONMiR-145 inhibits drug resistance to L-OHP of HCT116 cells through suppressing the expression of target gene GPR98.

ATP Binding Cassette Transporter, Sub-Family B ; drug effects ; ATP-Binding Cassette, Sub-Family B, Member 1 ; drug effects ; Cell Line, Tumor ; drug effects ; physiology ; Colorectal Neoplasms ; physiopathology ; Down-Regulation ; drug effects ; genetics ; Drug Resistance, Neoplasm ; drug effects ; genetics ; physiology ; HCT116 Cells ; drug effects ; physiology ; Humans ; In Vitro Techniques ; MicroRNAs ; genetics ; pharmacology ; Multidrug Resistance-Associated Proteins ; drug effects ; Organoplatinum Compounds ; pharmacology ; PTEN Phosphohydrolase ; drug effects ; RNA, Messenger ; Receptors, G-Protein-Coupled ; drug effects ; genetics

Oxaliplatin is a key drug in chemotherapy of colorectal cancer (CRC). However, its efficacy is unsatisfied due to drug resistance of cancer cells. In this study, we tested whether a natural agent, ursolic acid, was able to enhance the efficacy of oxaliplatin for CRC. Four CRC cell lines including SW480, SW620, LoVo, and RKO were used as in vitro models, and a SW620 xenograft mouse model was used in further in vivo study. We found that ursolic acid inhibited proliferation and induced apoptosis of all four cells and enhanced the cytotoxicity of oxaliplatin. This effect was associated with down-regulation of Bcl-xL, Bcl-2, survivin, activation of caspase-3, 8, 9, and inhibition of KRAS expression and BRAF, MEK1/2, ERK1/2, p-38, JNK, AKT, IKKα, IκBα, and p65 phosphorylation of the MAPK, PI3K/AKT, and NF-κB signaling pathways. The two agents also showed synergistic effects against tumor growth in vivo. In addition, ursolic acid restored liver function and body weight of the mice treated with oxaliplatin. Thus, we concluded that ursolic acid could enhance the therapeutic effects of oxaliplatin against CRC both in vitro and in vivo, which offers an effective strategy to minimize the burden of oxaliplatin-induced adverse events and provides the groundwork for a new clinical strategy to treat CRC.
Animals ; Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Cell Line, Tumor ; Colorectal Neoplasms ; drug therapy ; metabolism ; pathology ; Drug Synergism ; Female ; Humans ; Mice ; Mice, Nude ; Neoplasm Proteins ; metabolism ; Organoplatinum Compounds ; agonists ; pharmacology ; Oxaliplatin ; Triterpenes ; agonists ; pharmacology ; Xenograft Model Antitumor Assays

OBJECTIVETo investigate the effect of bafilomycin A1 (BAF) on the cell proliferation, invasiveness, apoptosis, and oxaliplatin sensitivity in gastric cancer MGC-803 cells.

METHODSMGC-803 cells were divided into control group, BAF group, oxaliplatin group, and BAFµ oxaliplatin group. MTT assay and plate clone formation assay were used to assess the viability and colony forming ability of the cells after the treatments. The expression of nucleosomes in the cells was examined with ELISA. The cell migration and invasion after the treatments were evaluated. Western blotting was performed to detect the expression of Bcl-2 and Bax in the treated cells, and scanning electron microscopy, immunohistochemistry and Western blotting were employed to to observe the cell autophagy.

RESULTSCompared with the control cells, the cells treated with BAF showed a substantial decrease in autophagosome accumulation with attenuated cell proliferation, migration and invasion. Compared with cells treated with oxaliplatin alone, the cells treated with both BAF and oxaliplatin showed significantly lowered autophagosome accumulation, suppressed cell proliferation, migration and invasion, increased cell apoptosis, increased Bax expression and lowered Bcl-2 expression.

CONCLUSIONBAF can inhibit the proliferation and invasiveness of MGC-803 cells, promote cell apoptosis by inhibiting autophagy, and enhances the sensitivity of the cells to oxaliplatin.

Apoptosis ; Autophagy ; Cell Line, Tumor ; drug effects ; Cell Movement ; Cell Proliferation ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Macrolides ; pharmacology ; Organoplatinum Compounds ; pharmacology ; Stomach Neoplasms ; pathology

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

OBJECTIVETo investigate the effects of total flavonoids of Litsea Coreana (TFLC) on the gap junction (GJ) intercellular communication in TM3 testicular Leydig cells and whether TFLC can reduce the cytotoxicity of oxaliplatin (OHP) in vitro.

METHODSWe detected the effect of TFLC on the dye spread of the in vitro cultured TM3 cells by parachute assay, observed changes in the expression of connexin 43 (Cx43) total protein in the TFLC-treated TM3 cells by Western blot, and determined the effects of TFLC on the expression of Cx43 on the membrane of the TM3 cells by immunofluorescence assay and on the cytotoxicity of OHP by MTT assay.

RESULTSTFLC obviously enhanced the GJ function with the increasing of the TFLC concentration in the TM3 cells. Western blot and immunofluorescence assay confirmed that TFLC significantly enhanced the expression of Cx43 total protein and Cx43 expression on the membrane of the TM3 cells. MTT assay showed that at a high cell density (confluent with GJ formation), 20 microg/ml TFLC enhanced the GJ function of the TM3 cells and reduced the cytotoxicity of OHP (P < 0.05), while at a low density (preconfluent with no GJ formation), TFLC exhibited no effect on the cytotoxicity of OHP (P > 0.05).

CONCLUSIONTFLC increases the Cx43 expression and GJ function in normal TM3 Leydig cells, and the enhancement of GJ function reduces the cytotoxicity of OHP.

Antineoplastic Agents ; toxicity ; Cell Communication ; drug effects ; physiology ; Cell Count ; Connexin 43 ; metabolism ; Flavonoids ; pharmacology ; Gap Junctions ; drug effects ; Humans ; In Vitro Techniques ; Leydig Cells ; drug effects ; ultrastructure ; Litsea ; chemistry ; Male ; Organoplatinum Compounds ; antagonists & inhibitors ; toxicity ; Proteins ; metabolism

OBJECTIVETo observe the effect of curcumin combined folinic acid fluorouracil oxaliplatin (FOLFOX) on the gastric adenocarcinoma cell line BGC-823 and to explore its possible mechanisms.

METHODSCells were divided into five groups, i.e. the blank control group, the curcumin group, the FOLFOX group (0.1 mmol/L 5-FU +5 micromol/L oxaliplatin), and the curcumin combined FOLFOX group. CCK-8 was used to detect cell activity. The cell apoptosis was observed using Hoechst dyeing. Caspase-3 test kit was applied to test Caspase-3 vitality. The mRNA expressions of Bcl-2 and Bax were detected by real time fluorescent quantitative PCR. The expressions of Bcl-2 and Bax protein were determined by Western blot.

RESULTSThe BGC-823 cells' proliferation could be inhibited, apoptosis induced, the Caspase-3 activity increased, expressions of Bcl-2 mRNA and Bcl-2 protein lowered, while Bax mRNA and Bax protein expressions increased in each medicated group. Besides, the efficacy of the curcumin combined FOLFOX group was superior to that of the curcumin group and the FOLFOX group, showing statistical difference (P < 0.01).

CONCLUSIONCurcumin combined FOLFOX could significantly inhibit the proliferation of BGC-823 cells possibly via promoting Bax expression and Caspase-3 activity, inhibiting Bcl-2 expression, thus inducing apoptosis.

Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Curcumin ; pharmacology ; Fluorouracil ; pharmacology ; Humans ; Leucovorin ; pharmacology ; Organoplatinum Compounds ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Stomach Neoplasms ; pathology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo study the role of BH3-only gene in oxaliplatin-induced apoptosis of human colon cancer cell line, and to explore the associated mechanisms.

METHODSTwo strains of human colon cancer cell line SW480 and HT29 were selected, and treated respectively with different concentrations of oxaliplatin (0.3, 0.6, 1.25, 2.5, 5, 10 and 20 mg/L). Cell growth and inhibition were detected by MTT method. Apoptosis was measured by flow cytometry. Bim and PUMA expressions were examined by fluorescence quantitative PCR.

RESULTSAfter treatment of different oxaliplatin concentrations in human colon carcinoma cells SW480 line, the cell growth was inhibited in a dose-dependent manner, while Bim and PUMA expressions were significantly up-regulated. While HT29 cell lines received the same treatment, no obvious inhibition of cell growth and up-regulation of Bim and PUMA expression were found. When SW480 cells were exposed to 5 mg/L and 10 mg/L of oxaliplatin for 24 h, the early apoptotic rates were (4.87±0.55)% and (12.10±1.04)%; for 48 h, the early apoptotic rates were (11.47±0.85)% and (30.07±2.01)%; for 72 h, the early apoptotic rates were (28.99±2.12)% and (38.32±3.15)% respectively, which were all significantly higher than those in control group [(0.30±0.10)%, (0.40±0.10)% and (0.50±0.20)%, all P<0.01]. In HT29 cells, the differences of apoptotic rates between oxaliplatin treatment group and control group were not statistically significant (all P>0.05).

CONCLUSIONSOxaliplatin can inhibit colon cancer cell line SW480 growth and induce apoptosis. Induction of apoptosis of colon cancer cells by oxaliplatin may be associated with the up-regulation of BH3-only proteins, Bim and PUMA.

Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Bcl-2-Like Protein 11 ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; pathology ; Humans ; Membrane Proteins ; metabolism ; Organoplatinum Compounds ; pharmacology ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism

OBJECTIVETo investigate the effects of a Chinese herbal extract Songyou Yin on residual hepatocellular carcinoma after chemotherapy in nude mice and the relevant mechanisms.

METHODSOrthotopic nude mouse models bearing residual hepatocellular carcinoma after chemotherapy was established using human liver carcinoma MHCC97L cells. Three different doses of Songyon Yin (2.1 g/kg, 4.2 g/kg and 8.4 g/kg) were administered to the mice in the trial groups by intragastric gavage, respectively. The mice in the control group were administered physiological saline. The tumor growth, metastasis and survival in the mice of each group were recorded. The corresponding mechanisms were studied.

RESULTSThe pulmonary metastasis rates of the control group and 2.1g/kg, 4.2g/kg, 8.4g/kg Songyou Yin treatment group were 86.7%, 73.3%, 40.0%, and 20.0%, respectively, and the survivals of these groups were 53.83 ± 4.71, 56.50 ± 6.09, 66.67 ± 5.61, 81.17 ± 7.36 days, respectively. Compared with the mice in the control group, mice in the 4.2 g/kg, 8.4 g/kg Songyou Yin treatment groups had a lower pulmonary metastasis rate (P = 0.021 and P = 0.001, respectively) and longer survival (P = 0.002 and P = 0.001, respectively). A restoration of E-cadherin expression and a concomitant reduction of N-cadherin expression were detected in the tumors of the 4.2 g/kg and 8.4 g/kg Songyou Yin treatment groups.

CONCLUSIONSSongyou Yin effectively inhibits the invasion and metastasis of the residual hepatocellular carcinoma after chemotherapy in nude mice through attenuating the epithelia-mesenchymal transition and prolongs the survival. Songyon Yin may have potential to promote the efficacy of chemotherapy in hepatocellular carcinoma.

Animals ; Antineoplastic Agents ; therapeutic use ; Antineoplastic Agents, Phytogenic ; isolation & purification ; pharmacology ; Cadherins ; metabolism ; Carcinoma, Hepatocellular ; drug therapy ; metabolism ; pathology ; Cell Line, Tumor ; Drug Combinations ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Epithelial-Mesenchymal Transition ; drug effects ; Humans ; Liver Neoplasms ; drug therapy ; metabolism ; pathology ; Lung Neoplasms ; secondary ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Neoplasm, Residual ; metabolism ; pathology ; Organoplatinum Compounds ; therapeutic use ; Plants, Medicinal ; chemistry ; Random Allocation ; Survival Rate ; Tumor Burden ; drug effects ; Xenograft Model Antitumor Assays

OBJECTIVETo investigate the effect of Oxaliplatin (L-OHP) on cell cycle in hepatocellular carcinoma cell line HepG2 and the involved mechanism.

METHODSInhibitory effect of L-OHP on the proliferation of HepG2 cells was determined by MTT assay. Cell cycle distribution was shown by flow FCM. The expression levels of cyclinD1, CDK2, CDK4, p16, p21, p53 were detected by RT-PCR and Western blot.

RESULTSMTT method revealed that L-OHP inhibited proliferation of hepatocellular carcinoma HepG2 cells in a dose- and time-dependent manner. L-OHP induced S cell cycle arrest in HepG2 cell; down-regulated the levels of CDK4, cyclinD1 and up-regulated the levels of p21, p53. There were no significant changes of CDK2 and p16 after L-OHP treatment.

CONCLUSIONL-OHP inhibits the proliferation of HepG2 cells by blocking cell at S stage, which may be resulted from the activity of CDK4, CyclinD1 and p21.

Carcinoma, Hepatocellular ; drug therapy ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Hep G2 Cells ; Humans ; Liver Neoplasms ; drug therapy ; Organoplatinum Compounds ; pharmacology ; Tumor Suppressor Protein p53 ; metabolism