BACKGROUND: Growing evidence suggests that long non-coding RNAs (lncRNAs) exert pivotal roles in fostering chemoresistance across diverse tumors. Nevertheless, the precise involvement of lncRNAs in modulating chemoresistance within the context of gallbladder cancer (GBC) remains obscure. This study aimed to uncover how lncRNAs regulate chemoresistance in gallbladder cancer, offering potential targets to overcome drug resistance. METHODS: To elucidate the relationship between gemcitabine sensitivity and small nucleolar RNA host gene 1 ( SNHG1 ) expression, we utilized publicly available GBC databases, GBC tissues from Renji Hospital collected between January 2017 and December 2019, as well as GBC cell lines. The assessment of SNHG1, miR-23b-3p, and phosphatase and tensin homolog (PTEN) expression was performed using in situ  hybridization, quantitative real-time polymerase chain reaction, and western blotting. The cell counting kit-8 (CCK-8) assay was used to quantify the cell viability. Furthermore, a GBC xenograft model was employed to evaluate the impact of SNHG1 on the therapeutic efficacy of gemcitabine. Receiver operating characteristic (ROC) curve analyses were executed to assess the specificity and sensitivity of SNHG1. RESULTS: Our analyses revealed an inverse correlation between the lncRNA SNHG1 and gemcitabine resistance across genomics of drug sensitivity in cancer (GDSC) and Gene Expression Omnibus (GEO) datasets, GBC cell lines, and patients. Gain-of-function investigations underscored that SNHG1 heightened the gemcitabine sensitivity of GBC cells in both in vitro and in vivo  settings. Mechanistic explorations illuminated that SNHG1 could activate PTEN -a commonly suppressed tumor suppressor gene in cancers-thereby curbing the development of gemcitabine resistance in GBC cells. Notably, microRNA (miRNA) target prediction algorithms unveiled the presence of miR-23b-3p binding sites within SNHG1 and the 3'-untranslated region (UTR) of PTEN . Moreover, SNHG1 acted as a sponge for miR-23b-3p, competitively binding to the 3'-UTR of PTEN , thereby amplifying PTEN expression and heightening the susceptibility of GBC cells to gemcitabine. CONCLUSION The SNHG1/miR-23b-3p/PTEN axis emerges as a pivotal regulator of gemcitabine sensitivity in GBC cells, holding potential as a promising therapeutic target for managing GBC patients.
Humans ; Deoxycytidine/pharmacology* ; PTEN Phosphohydrolase/genetics* ; Gemcitabine ; RNA, Long Noncoding/metabolism* ; MicroRNAs/genetics* ; Gallbladder Neoplasms/genetics* ; Cell Line, Tumor ; Animals ; Mice ; Drug Resistance, Neoplasm/genetics* ; Mice, Nude ; Antimetabolites, Antineoplastic ; Gene Expression Regulation, Neoplastic

OBJECTIVETo investigate the inhibitory effect of classic demethylating drug 5-aza-2'-deoxycytidine (5-Aza-CdR) on the growth of human lung adenocarcinoma cells in nude mouse xenograft models, and to observe its effect on methylation status and expression of TFPI-2 gene in the nude mouse xenograft tissues.

METHODSThe nude mouse xenograft model was established by subcutaneous inoculation of human lung adenocarcinoma A549 cells. According to different doses of 5-Aza-CdR, the tumor-bearing nude mice were randomly divided into experimental groups (0.5 mg/kg group, 1 mg/kg group, 2 mg/kg group) and control group (0 mg/kg group). The tumor growth in the nude mice was observed. The methylation status and the expression of TFPI-2 gene mRNA and protein were detected by methylation specific polymerase chain reaction, real-time fluorescent quantitative polymerase chain reaction and Western blot assay.

RESULTSThe nude mice were euthanized at 28 days after intraperitoneal injection of 5-Aza-CdR. The body weight of tumor-bearing nude mice was (27.12 ± 0.38) g in the 0 mg/kg group, (26.80 ± 0.18) g in the 0.5 mg/kg group, (26.67 ± 0.28) g in the 1 mg/kg group, and (26.50 ± 0.26) g in the 2 mg/kg group, showing no significant difference among them (P > 0.05). The volume of xenograft tumors in the 0 mg/kg group was (709.22 ± 2.87)mm³, (400.67 ± 2.68)mm³ in the 0.5 mg/kg group, (285.71 ± 2.91)mm³ in the 1 mg/kg group, and (230.44 ± 3.15)mm³ in the 2 mg/kg group, showing a significant difference (P < 0.05). There were complete methylation of TFPI-2 gene in the 0 mg/kg group, incomplete methylation in the 0.5 and 1 mg/kg groups, and unmethylation in the 2 mg/kg group. The relative mRNA level in the 0, 0.5, 1, 2 mg/kg groups were 1.00 ± 0.00, 1.67 ± 0.07, 3.40 ± 0.24, and 5.55 ± 0.61, respectively (P < 0.05). The relative expression level of TFPI-2 protein in the 0, 0.5, 1, 2 mg/kg groups was 0.18 ± 0.02, 0.36 ± 0.01, 0.64 ± 0.02, and 0.81 ± 0.20, respectively (P < 0.05).

CONCLUSIONS5-Aza-CdR suppresses the tumor growth of human lung adenocarcinoma cells in nude mouse xenograft models, and induces expression of TFPI-2 gene in the xenograft tumor cells. The mechanism might be that 5-Aza-CdR induces re-expression of demethylated TFPI-2 gene by demethylation, and thus inhibits the growth and proliferation of human lung adenocarcinoma cells.

Adenocarcinoma ; drug therapy ; pathology ; Animals ; Antimetabolites, Antineoplastic ; pharmacology ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Proliferation ; drug effects ; DNA Methylation ; Disease Models, Animal ; Gene Expression Regulation, Neoplastic ; Glycoproteins ; genetics ; Heterografts ; Humans ; Lung Neoplasms ; drug therapy ; pathology ; Mice ; Mice, Nude ; RNA, Messenger ; metabolism ; Random Allocation

OBJECTIVEThe aim of this study was to explore the effect of SPARC on the anti-cancer effect of gemcitabine and underlying mechanism in pancreatic cancer.

METHODSAfter treating with gemcitabine, the proliferation rate of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells was detected by MTT assay. The cell cycle distribution and cell apoptosis in each group were examined by flow cytometry, and the capability of clone formation was tested by adhesion-dependent clone formation assay. The apoptosis-related proteins were analyzed by Western blot.

RESULTSThe growth of pancreatic cancer cells was inhibited by gemcitabine in a time-dependent and dose-dependent manner. Its IC50 at 24, 48, and 72-h was (40.1 ± 2.5) µmol/L, (15.0 ± 0.5) µmol/L and (6.6 ± 0.1) µmol/L, respectively. The overexpression of SPARC increased the inhibitory effect of gemcitabine on growth of pancreatic cancer MIA PaCa2/SPARC69 cells, presenting a dose- and time- dependent manner. Its IC50 at 24, 48, 72 h was (24.3 ± 1.5) µmol/L, (7.7 ± 0.3) µmol/L and (4.8 ± 0.2) µmol/L, respectively. The clone formation assay showed that before gemcitabine treatment, the clone numbers of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (2350 ± 125), (2130 ± 120) and (1567 ± 11), respectively. After gemcitabine treatment, the clone numbers of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were ( 1674 ± 79) , (1587 ± 94) and (557 ± 61), respectively. The overexpression of SPARC enhanced the chemosensitivity of MIA PaCa2 cells to gemcitabine chemotherapy. After treating with 10 µmol/L gemcitabine for 48 h, the ratio of G0/G1 cells in MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (56.0 ± 5.5)%, (55.0 ± 4.5)% and (68.0 ± 7.0)%, respectively. The cells arrested at G0/G1 phase were significantly increased in the MIA PaCa2/SPARC69 cells. The apoptosis rates of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (22.4 ± 2.5)%, (19.9 ± 2.0)% and (37.7 ± 3.9)%, respectively, indicating that overexpression of SPARC enhanced the gemcitabine-induced apoptosis in MIA PaCa2 cells. The Western blot analysis showed that, compared with MIA PaCa2 and MIA PaCa2/V cells, the expression of caspase-2, -8, -9 and cleaved PARP protein was significantly increased, while the expression of Bcl-2 was not changed significantly in the MIA PaCa2/SPARC69 cells.

CONCLUSIONSPARC can enhance the chemosensitivity of pancreatic cancer cells to gemcitabine via regulating the expression of apoptosis-related proteins.

Antimetabolites, Antineoplastic ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Caspase 2 ; metabolism ; Caspase 8 ; metabolism ; Caspase 9 ; metabolism ; Cell Cycle ; drug effects ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cysteine Endopeptidases ; metabolism ; Deoxycytidine ; administration & dosage ; analogs & derivatives ; pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Neoplasm ; Humans ; Osteonectin ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Poly(ADP-ribose) Polymerases ; metabolism ; Time Factors

OBJECTIVETo investigate the effects of E2F-1 gene silencing on multidrug resistance of human gastric cancer SGC7901/DDP cells and its possible mechanisms.

METHODSGastric cancer SGC7901/DDP cells were seeded in 6 well plates and divided into three groups: the experimental group, blank control and the negative control groups. For the experimental group, the SGC7901/DDP cells were transfected with recombinant lentivirus vector (Lv-shRNA-E2F-1), while the negative control with an control lentiviral vector (Lv-shRNA-NC) and the blank control with no treatment. The E2F-1 protein level was analyzed by Western blot. MTT assay was used to detect the half maximal inhibitory concentration (IC50) of three chemotherapy drugs including adriamycin, 5-fluorouracil (5-Fu) and cisplatine (DDP) of the three cell groups. Flow cytometry (FCM) was used to detect the pump-out rate of adriamycin and apoptosis rate of the three cell groups. Semi-quantitative RT-PCR and Western blot were also used to detect the protein and mRNA levels of multidrug resistance-associated genes (MDR1, MRP) and apoptosis-related genes (c-Myc, Skp2, cyclinD1).

RESULTSThe expression of E2F-1 protein in the experimental group was significantly lower than that in the negative control and blank control groups (0.794 ± 0.033 vs. 1.487 ± 0.082 vs. 1.511 ± 0.084, P < 0.01). The IC50 of the three chemotherapy drugs (adriamycin, 5-Fu and cisplatine) in the experimental group was significantly lower than that of the negative control and blank control groups, respectively (P < 0.01). Compared with the negative control and blank control groups, the pump-out rate of adriamycin of the experimental group was significantly declined [(0.16 ± 0.01)% vs. (0.37 ± 0.01)% vs. (0.35 ± 0.02)%, P < 0.01]. However, the apoptosis rate of the experimental group was significantly higher than that of the negative control and blank control groups [(33.82 ± 1.26)% vs. (17.34 ± 0.81)% vs. (13.16 ± 1.06)%, P < 0.01]. The results of RT-PCR and Western blot assays showed that mRNA and protein expressions of five genes (MDR1, MRP, CyclinD1, c-Myc, Skp2) in the experimental group were significantly lower than that in the negative control and blank control groups, respectively (P < 0.01).

CONCLUSIONSE2F-1 gene silencing enhances the chemosensitivity of gastric cancer SGC7901/DDP cells to the chemotherapeutic drugs, directly or indirectly downregulated the expression of MDR1 and MRP, and finally reverses the multidrug resistance of the gastric cancer cells. The mechanism may be associated with the suppression of cyclinD1, c-Myc and Skp2.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Antibiotics, Antineoplastic ; pharmacology ; Antimetabolites, Antineoplastic ; pharmacology ; Antineoplastic Agents ; pharmacology ; Apoptosis ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Cyclin D1 ; genetics ; metabolism ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; E2F1 Transcription Factor ; genetics ; metabolism ; Fluorouracil ; pharmacology ; Gene Silencing ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-myc ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; S-Phase Kinase-Associated Proteins ; genetics ; metabolism ; Stomach Neoplasms ; metabolism ; pathology ; Transfection

This study was aimed to investigate the effects of the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) and histone deacetylase inhibitor trichostatin A (TSA) on DLC-1 gene transcription regulation and molecular biological behaviours in the human multiple myeloma RPMI-8226 cells. The cells were treated respectively with 5-Aza-CdR and TSA alone, or the both combination; the cell proliferation and apoptosis, DLC-1 expression, the protein expression of Ras homolog family member A (RhoA) and Ras-related C3 botulinum toxin substrate 1 (Rac1) were examined by CCK-8 method, RT-PCR and ELISA, respectively. The results showed that the 5-Aza-CdR and TSA had cell growth inhibitory and apoptosis-inducing effects in dose-dependent manner (P < 0.05). Compared with a single drug (5-Aza-CdR or TSA alone), the effects were significantly enhanced after treatment with the combination of 5-Aza-CdR and TSA (P < 0.05). DLC-1 was weakly expressed in the control group; the treatment with 5-Aza-CdR alone enhanced its re-expression dose-dependently (P < 0.05). Compared with 5-Aza-CdR alone, 5-Aza-CdR plus TSA enhanced DLC-1 re-expression significantly.Compared with the control, 5-Aza-CdR and TSA significantly decreased RhoA and Rac1 protein expression (P < 0.05). It is concluded that 5-Aza-CdR and TSA can effectively reverse DLC-1 expression of RPMI-8226 cells; TSA has a synergistic effect on its re-expression. 5-Aza-CdR and TSA have significant cell growth inhibitory and apoptosis-inducing effects on RPMI-8226 cells. These effects may be related to the inhibition of Rho/Rho kinase signalling pathway.
Antimetabolites, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; Azacitidine ; administration & dosage ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; GTPase-Activating Proteins ; metabolism ; Gene Expression ; drug effects ; Humans ; Hydroxamic Acids ; administration & dosage ; pharmacology ; Multiple Myeloma ; genetics ; pathology ; Tumor Suppressor Proteins ; metabolism

Mcl-1 and Bcl-xL, key anti-apoptotic proteins of the Bcl-2 family, have attracted attention as important molecules in the cell survival and drug resistance. In this study, we investigated whether inhibition of Bcl-xL influences cell growth and apoptosis against simultaneous treatment of resveratrol and clofarabine in the human malignant mesothelioma H-2452 cells. Resveratrol and clofarabine decreased Mcl-1 protein levels but had little effect on Bcl-xL levels. In the presence of two compounds, any detectable change in the Mcl-1 mRNA levels was not observed in RT-PCR analysis, whereas pretreatment with the proteasome inhibitor MG132 led to its accumulation to levels far above basal levels. The knockdown of Bcl-xL inhibited cell proliferation with cell accumulation at G2/M phase and the appearance of sub-G0/G1 peak in DNA flow cytometric assay. The suppression of cell growth was accompanied by an increase in the caspase-3/7 activity with the resultant cleavages of procaspase-3 and its substrate poly (ADP-ribose) polymerase, and increased percentage of apoptotic propensities in annexin V binding assay. Collectively, our data represent that the efficacy of resveratrol and clofarabine for apoptosis induction was substantially enhanced by Bcl-xL-lowering strategy in which the simultaneous targeting of Mcl-1 and Bcl-xL could be a more effective strategy for treating malignant mesothelioma.
Adenine Nucleotides/*pharmacology ; Antimetabolites, Antineoplastic/*pharmacology ; Apoptosis/*drug effects ; Arabinonucleosides/*pharmacology ; Caspase 3/metabolism ; Caspase 7/metabolism ; Cell Line, Tumor ; Cell Proliferation/drug effects ; G2 Phase Cell Cycle Checkpoints/drug effects ; Gene Knockdown Techniques ; Humans ; Leupeptins/pharmacology ; Lung Neoplasms/metabolism/pathology ; M Phase Cell Cycle Checkpoints/drug effects ; Mesothelioma/metabolism/pathology ; Myeloid Cell Leukemia Sequence 1 Protein/antagonists & inhibitors/genetics/metabolism ; RNA Interference ; RNA, Messenger/metabolism ; RNA, Small Interfering/metabolism ; Stilbenes/*pharmacology ; bcl-X Protein/antagonists & inhibitors/*genetics/*metabolism

BACKGROUNDCancer testis antigens (CTAs) are a novel group of tumor associated antigens. Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism, thus enhance the immunogenicity of leukemia cells. However, few researches have ever focused on the questions that whether this immunostimulatory effect of decitabine could induce autologous CTA specific cytotoxic T lymphocytes (CTLs) in vivo, and if so, whether this effect contributes to disease control. In this study, we aimed to show that decitabine could induce specific autologous CTLs against some mouse CTAs in leukemia cells in vitro and in vivo.

METHODSSeveral mouse CTAs were screened by RT-PCR. CTL specific to one of the CTAs named P1A was detected and sorted by P1A specific dimer by flow cytometry. The activity of specific CTLs was measured by real time RT-PCR.

RESULTSWe firstly screened expression of some CTAs in mouse leukemia cells before and after decitabine treatment and found that decitabine treatment did up-regulate expression of many CTAs. Then we measured the CTLs' activity specific to a mouse CTA P1A in vivo and showed that this activity increased after decitabine treatment. Finally, we sorted these in vivo induced P1A specific CTLs by flow cytometry and demonstrated their cytotoxicity against decitabine treated leukemia cells.

CONCLUSIONSOur study showed the autologous immune response induced by decitabine in vivo. And more importantly, we firstly proved that this response may contribute to disease control. We believe that this immunostimulatory effect is another anti-cancer mechanism of decitabine, and this special effect would inspire new applications of decitabine in the field of leukemia treatment in the future.

Animals ; Antigens, Neoplasm ; metabolism ; Antimetabolites, Antineoplastic ; pharmacology ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Flow Cytometry ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; T-Lymphocytes, Cytotoxic ; drug effects ; metabolism

5-Flucytosine (5-FC) could be changed to 5-fluorouracil (5-FU) by cytosine deaminase (CD), the latter is able to kill cancer cells. However, there is no efficient method to deliver the CD gene into the tumor cells, which hampers the application of the suicide gene system. In this experiment, for the first time, the NDV has been utilized as a vector to deliver the CD gene into the cancer cells, the virus can infect the cancer cells specifically, replicate and assemble, while the cytosine deaminase is expressed. Then the CD converts the prodrug 5-FC into 5-FU to achieve the purpose of inhibiting tumor. Firstly, the whole genome of E. coli JM109 was extracted, and the CD gene was obtained by cloning method. Then the CD and IRES-EGFP were ligated into the pEE12.4 expression vector to become a recombinant pEE12.4IE-CD eukaryotic expression plasmid. The human liver cancer cells were transfected with the plasmid. The cells were treated with different concentrations of 5-FC, MTT method was used to determine the killing effect of CD/5-FC system on the human liver cancer cells. The cell deaths were 18.07%, 42.98% and 62.20% respectively when the concentrations of prodrug were at 10, 20 and 30 mmol x L(-1). In 5-FC acute toxicity experiment, Kunming mice were injected with different concentrations of 5-FC at intervals of 1:0.5. The LD50 of 5-FC through iv injection was determined by improved Karber's method, the LD50 was 507 mg x kg(-1) and the 95% confidence limit was 374-695 mg x kg(-1). According to the maximum LD0 dose of the LD50, the maximum safe dose was 200 mg x kg(-1). Body weight and clinic symptoms of the experimental animals were observed. These results laid the foundation to verify the antitumor effect and safety of CD/5-FC system in animal models. The CD gene was ligated into the NDV (rClone30) carrier, then the tumor-bearing animal was established to perform the tumor inhibiting experiment. The result showed that the recombinant rClone30-CD/5-FC system has a high antitumor activity in vivo. To summarize, CD gene has been cloned and its bioactivity has been confirmed in the mammalian cells. It is the first time in this study to utilize the recombinant NDV to deliver the CD gene into the tumor cells; our result proves the rClone30-CD/5-FC system is a potential method for cancer therapy.
Animals ; Antimetabolites, Antineoplastic ; metabolism ; pharmacology ; Cell Death ; drug effects ; Chick Embryo ; Cytosine Deaminase ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Flucytosine ; metabolism ; pharmacology ; Fluorouracil ; metabolism ; pharmacology ; Genetic Vectors ; Hep G2 Cells ; Humans ; Lethal Dose 50 ; Liver Neoplasms, Experimental ; pathology ; Mice ; Newcastle disease virus ; genetics ; Plasmids ; Recombinant Proteins ; genetics ; metabolism ; Transfection ; Tumor Burden ; drug effects

OBJECTIVETo investigate the effect of 5-Aza-2'-deoxycytidine (5-Aza-dC) on TIP30 gene expression and the relationship between TIP30 expression and the sensitivity to 5-fluouracil (5-Fu) in colorectal cancer cells.

METHODSThe methylation profile of TIP30 gene in HCT116 colorectal cancer cells was determined by methylation-specific PCR. The levels of TIP30 mRNA and protein were determined by RT-PCR and Western blot after the 5-Aza-dC treatment. MTT assay was used to detect the chemosensitivity of HCT116 cells to 5-Fu.

RESULTSTIP30 gene displayed complete DNA methylation in the HCT116 cells without 5-Aza-dC pretreatment. After the 5-Aza-dC treatment for 3 days, only demethylating PCR amplification product was detected and TIP30 gene showed DNA demethylation. With the prolongation of the time of removal of 5-Aza-dC treatment, methylated and demethylated PCR amplification products were observed and TIP30 gene displayed both DNA methylation and DNA demethylation in the colorectal cancer cells. At the day 10 after removal of 5-Aza-dC, methylating PCR amplification product appeared and TIP30 gene showed DNA methylation. No expressions of TIP30 mRNA and protein were detected in the HCT116 cells untreated with 5-Aza-dC. After the treatment of 5-Aza-dC for 3 d and then removed the 5-Aza-dC, the expressions of TIP30 mRNA and protein were increased obviously. With the prolonged time after 5-Aza-dC removal, the expressions of TIP30 mRNA and protein decreased and reached the lowest level on day 10. The IC50 values of 5-Fu were 41.62, 33.17 and 4.96 µg/ml in the HCT116 cells pretreated with 5-Aza-dC, d0 and d10 with the drug removal after drug treatment for 3 d, respectively.

CONCLUSIONSThe results of this study show that the expression of TIP30 gene may be associated with its DNA methylation status and may affect the sensitivity of colorectal cancer cells to 5-Fu.

Acetyltransferases ; genetics ; metabolism ; Antimetabolites, Antineoplastic ; pharmacology ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Proliferation ; drug effects ; CpG Islands ; genetics ; DNA Methylation ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Fluorouracil ; pharmacology ; Gene Expression Regulation, Neoplastic ; HCT116 Cells ; Humans ; Inhibitory Concentration 50 ; RNA, Messenger ; metabolism ; Transcription Factors ; genetics ; metabolism

OBJECTIVETo investigate the effect of demethylating agent 5-aza-2'-deoxycytidine (5-Aza-CdR) on the growth of human pancreatic cancer cell line MiaPaca2 and the expression and methylation of tumor suppressor gene RUNX3.

METHODSHuman pancreatic cancer cell line MiaPaca2 cells were treated with different concentrations of 5-Aza-CdR. Morphological changes of MiaPaca2 cells were observed by light microscopy. The activity of cell proliferation was analyzed by MTT assay. The changes of RUNX3 mRNA expression were detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Changes of RUNX3 gene methylation was detected by methylation-specific polymerase chain reaction.

RESULTSMiaPaca2 cells were treated with 2.5, 5, 10 and 20 µmo1/L 5-Aza-CdR, respectively. The inhibition rates of MiaPaca2 cells treated for 24 h were (9.17 ± 2.15)%, (10.75 ± 2.04)%, (12.57 ± 1.64)% and (18.70 ± 1.51)%, respectively. The inhibition rates were (14.94 ± 1.68)%, (18.60 ± 1.57)%, (22.84 ± 1.58)% and (33.24 ± 1.53)%, respectively, after 48 h treatment; (21.46 ± 1.60)%, (28.62 ± 1.72)%, (35.14 ± 1.64)% and (45.06 ± 1.47)%, respectively, after 72 h treatment; and (26.35 ± 1.71)%, (34.48 ± 1.69)%, (40.05 ± 1.60)% and (49.99 ± 1.61)%, respectively, after 96 h treatment. The differences between inhibition rates of each experimental and control groups (0.00 ± 0.00)% were statistically significant (P < 0.05). At the same time, the inhibition rates of different concentration groups showed significant differences (P < 0.05). At 48 h, 72 h and 96 h, the inhibition rates of each pair concentration groups showed significant differences (P < 0.05). 5-Aza- CdR inhibited the growth of MiaPaca2 cells, and the higher the concentration, the stronger the inhibition after 24 h. 5-Aza-CdR also reversed the methylation status of RUNX3 gene, and restored the expression of RUNX3 mRNA with a dose-effect relationship.

CONCLUSIONSThe methylation of RUNX3 gene is significantly related with the occurrence and development of pancreatic cancer, and abnormal methylation of RUNX3 gene may contribute to the loss of RUNX3 mRNA expression. 5-Aza-CdR may effectively cause reversion of RUNX3 methylation, and treatment with 5-Aza-CdR can reactivate the gene expression and inhibit the cell growth. This may provide a new way for diagnosis and treatment of pancreatic cancer.

Antimetabolites, Antineoplastic ; administration & dosage ; pharmacology ; Azacitidine ; administration & dosage ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Core Binding Factor Alpha 3 Subunit ; genetics ; metabolism ; DNA Methylation ; drug effects ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Neoplastic ; Humans ; Pancreatic Neoplasms ; metabolism ; pathology ; RNA, Messenger ; metabolism