miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells.

JOURNAL/nrgr/04.03/01300535-202501000-00035/figure1/v/2024-05-14T021156Z/r/image-tiff Our previous study found that rat bone marrow-derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

IKVAV functionalized oriented PCL/Fe3O4 scaffolds for magnetically modulating DRG growth behavior.

The re-bridging of the deficient nerve is the main problem to be solved after the functional impairment of the peripheral nerve. In this study, a directionally aligned polycaprolactone/triiron tetraoxide (PCL/Fe3O4) fiber scaffolds were firstly prepared by electrospinning technique, and further then grafted with IKVAV peptide for regulating DRG growth and axon extension in peripheral nerve regeneration. The results showed that oriented aligned magnetic PCL/Fe3O4 composite scaffolds were successfully prepared by electrospinning technique and possessed good mechanical properties and magnetic responsiveness. The PCL/Fe3O4 scaffolds containing different Fe3O4 concentrations were free of cytotoxicity, indicating the good biocompatibility and low cytotoxicity of the scaffolds. The IKVAV-functionalized PCL/Fe3O4 scaffolds were able to guide and promote the directional extension of axons, the application of external magnetic field and the grafting of IKVAV peptides significantly further promoted the growth of DRGs and axons. The ELISA test results showed that the AP-10 F group scaffolds promoted the secretion of nerve growth factor (NGF) from DRG under a static magnetic field (SMF), thus promoting the growth and extension of axons. Importantly, the IKVAV-functionalized PCL/Fe3O4 scaffolds could significantly up-regulate the expression of Cntn2, PCNA, Sox10 and Isca1 genes related to adhesion, proliferation and magnetic receptor function under the stimulation of SMF. Therefore, IKVAV-functionalized PCL/Fe3O4 composite oriented scaffolds have potential applications in neural tissue engineering.

Cytotoxic phenazine and antiallergic phenoxazine alkaloids from an arctic Nocardiopsis dassonvillei SCSIO 502F.

Microbes well-adapted to the Arctic Ocean are promising for producing novel compounds, due to their fancy strategies for adaptation and being under-investigated. Two new phenazine alkaloids (1 and 2) and one new phenoxazine (3) were isolated from Nocardiopsis dassonvillei 502F, a strain originally isolated from Arctic deep-sea sediments. AntiSMASH analysis of the genome of Nocardiopsis dassonvillei 502F revealed the presence of 16 putative biosynthetic gene clusters (BGCs), including a phenazine BGC. Most of the isolated compounds were evaluated for their antibacterial, antiallergic, and cytotoxic activities. Among them, compounds 4 and 5 exhibited potent in vitro cytotoxic activities against osteosarcoma cell line 143B with IC50 values 0.16 and 20.0 µM, respectively. Besides, the results of antiallergic activities of compounds 6-8 exhibited inhibitory activities with IC50 values of 10.88 ± 3.05, 38.88 ± 3.29, and 2.44 ± 0.17 µg/mL, respectively (IC50 91.6 µM for the positive control loratadine).

[Effect of Nucleolin on Lymphoma Proliferation by Regulating Thymidine Kinase 1].

OBJECTIVE: To investigate the mechanism of nucleolin (NCL) involved in lymphoma proliferation by regulating thymidine kinase 1 (TK1). METHODS: Twenty-three patients with diffuse large B-cell lymphoma (DLBCL) were selected and divided into initial treatment group (14 cases) and relapsed/refractory group (9 cases). Serum TK1 and C23 protein in peripheral blood mononuclear cells were detected. Cell models of CA46-NCL-KD (CA46-NCL-knockdown) and CA46-NCL-KNC (CA46-NCL-knockdown negative control) were established by lentivirus vector mediated transfection in Burkitt lymphoma cell line CA46. The half maximal inhibitory concentration (IC50) of CA46-NCL-KD, CA46-NCL-KNC, and CA46 to adriamycin were detected by cell proliferation assay (MTS). The expression of NCL mRNA and protein in CA46-NCL-KD and CA46-NCL-KNC cells were dectected by Q-PCR and Western blot, respectively. The cell cycle of CA46-NCL-KD, CA46-NCL-KNC, and CA46 cells were detected by flow cytometry. The expression of TK1 protein in CA46-NCL-KD and CA46-NCL-KNC cells was detected by an enhanced chemiluminescence (ECL) dot blot assay. RESULTS: The level of serum TK1 in the initial treatment group was 0.43(0-30-1.01) pmol/L, which was lower than 10.56(2.19-14.99) pmol/L in the relapsed/refractory group (P<0-01), and the relative expression level of NCL protein in peripheral blood was also significantly lower. The IC50 of CA46-C23-KD cells to adriamycin was (0.147±0.02) µg/ml, which was significantly lower than (0.301±0.04) µg/ml of CA46-C23-KNC cells and (0.338±0.05) µg/ml of CA46 cells (P<0.05). Compared with CA46-NCL-KNC cells, the expression of NCL mRNA and protein, TK1 protein decreased in CA46-NCL-KD cells, and the proportion of S phase and G2/M phase also decreased, while G0/G1 phase increased in cell cycle. CONCLUSION: The increased expression of NCL in DLBCL and CA46 cells indicates low sensitivity to drug. NCL may participate in regulation of lymphoma proliferation by affecting TK1 expression, thereby affecting the drug sensitivity.

Nanoscale Treatment of Intervertebral Disc Degeneration: Mesenchymal Stem Cell Exosome Transplantation.

A common surgical disease, intervertebral disc degeneration (IVDD), is increasing at an alarming rate in younger individuals. Repairing damaged intervertebral discs (IVDs) and promoting IVD tissue regeneration at the molecular level are important research goals.Exosomes are extracellular vesicles (EVs) secreted by cells and can be derived from most body fluids. Mesenchymal stem cell-derived exosomes (MSC-exos) have characteristics similar to those of the parental MSCs. These EVs can shuttle various macromolecular substances, such as proteins, messenger RNAs (mRNAs), and microRNAs (miRNAs) and regulate the activity of recipient cells through intercellular communication. Reducing inflammation and apoptosis can significantly promote IVD regeneration to facilitate the repair of the IVD. Compared with MSCs, exosomes are more convenient to store and transport, and the use of exosomes can prevent the risk of rejection with cell transplantation. Furthermore, MSC-exo-mediated treatment may be safer and more effective than MSC transplantation. In this review, we summarize the use of bone marrow mesenchymal stem cells (BMSCs), adipose-derived mesenchymal stem cells (AMSCs), nucleus pulposus mesenchymal stem cells (NPMSCs), and stem cells from other sources for tissue engineering and use in IVDD. Here, we aim to describe the role of exosomes in inhibiting IVDD, their potential therapeutic effects, the results of the most recent research, and their clinical application prospects to provide an overview for researchers seeking to explore new treatment strategies and improve the efficacy of IVDD treatment.

The Effect of Human Bone Marrow Mesenchymal Stem Cell-Derived Exosomes on Cartilage Repair in Rabbits.

Mesenchymal stem cells (MSCs) have shown chondroprotective effects in cartilage repair. However, side effects caused by MSC treatment limit their application in clinic. As a cell-free therapy, MSC-derived exosomes (EXOs) have attracted much more attention in recent years. In the present study, we prepared EXOs from human bone marrow mesenchymal stem cells (hBMSCs) and examined their therapeutic potentials in cartilage repair. Our results showed that the prepared extracellular vesicles exhibit classical features of EXOs, such as cup-like shape, around 100 nm diameter, positive protein markers (CD81, TSG101, and Flotillin 1), and ability of internalization. In primary chondrocytes, the treatment of hBMSC-EXOs markedly increases cell viability and proliferation in a dose-dependent manner. Moreover, wound healing assay showed that hBMSC-EXOs accelerate cell migration in primary chondrocytes. JC-1 staining revealed that the mitochondrial membrane potential was enhanced by hBMSC-EXOs, indicating cell apoptosis was decreased in the presence of hBMSC-EXOs. In rabbits with articular cartilage defects, local administration with hBMSC-EXOs facilitates cartilage regeneration as evidenced by gross view and hematoxylin-eosin (H&E) and Saf-O/Fast Green staining. In addition, the International Cartilage Repair Society (ICRS) score was increased by the application of hBMSC-EXOs. Overall, our data indicate that the treatment with hBMSC-EXOs is a suitable cell-free therapy for treating cartilage defects, and these benefits are likely due to improved cell proliferation and migration in chondrocytes.

Improvement of sensory neuron growth and survival via negatively regulating PTEN by miR-21-5p-contained small extracellular vesicles from skin precursor-derived Schwann cells.

BACKGROUND: Patients with peripheral nerve injury (PNI) often suffer from hypoxic ischemic impairments, in particular when combined with vascular damage, causing neuronal dysfunction and death. Increasing attention has been paid on skin precursor-derived Schwann cells (SKP-SCs), and previous study has shown that SKP-SCs could promote sensory recovery after cell therapy for PNI, resembling the effect of naive SCs, and SKP-SC-derived extracellular vesicles (SKP-SC-EVs) are putatively supposed to be promising therapeutic agents for neural regeneration. METHODS: SKPs were induced to differentiate towards SCs with cocktail factors (N2, neuregulin-1ß, and forskolin) in vitro. SKP-SC-EVs were isolated by exoEasy Maxi Kit and characterized by morphology and phenotypic markers of EVs. Rat sensory neurons from dorsal root ganglions (DRGs) were primarily cultured in regular condition or exposed to oxygen-glucose-deprivation (OGD) condition. SKP-SC-EVs were applied to DRGs or sensory neurons, with LY294002 (a PI3K inhibitor) added; the effect on neurite outgrowth and cell survival was observed. Moreover, microRNA (miR) candidate contained in SKP-SC-EVs was screened out, and miR-mimics were transfected into DRG neurons; meanwhile, the negative regulation of PTEN/PI3K/Akt axis and downstream signaling molecules were determined. RESULTS: It was shown that SKP-SC-EVs could improve the neurite outgrowth of DRGs and sensory neurons. Furthermore, SKP-SC-EVs enhanced the survival of sensory neurons after OGD exposure by alleviating neuronal apoptosis and strengthening cell viability, and the expression of GAP43 (a neuron functional protein) in neurons was upregulated. Moreover, the neuro-reparative role of SKP-SC-EVs was implicated in the activation of PI3K/Akt, mTOR, and p70S6k, as well as the reduction of Bax/Bcl-2 ratio, that was compromised by LY294002 to some extent. In addition, transferring miR-21-5p mimics into sensory neurons could partly protect them from OGD-induced impairment. CONCLUSIONS: Sum up, SKP-SC-EVs could improve neurite outgrowth of DRG sensory neurons in physiological and pathological condition. Moreover, the in vitro therapeutic potential of SKP-SC-EVs on the survival and restoration of OGD-injured sensory neurons was evidenced to be associated with miR-21-5p contained in the small EVs and miR-21-5p/PTEN/PI3K/Akt axis.

[PLK1 Expression in Mantle Cell Lymphoma and Its Clinical Significance].

OBJECTIVE: To explore the expression level of PLK1 in mantle cell lymphoma(MCL), and the effect of silencing PLK1 gene by RNA interference on the cell proliferation, apoptosis, and cell cycle. METHODS: S-P immunohistochemistry technique was used to detect the expression of PLK1 in tissues of 42 patients with MCL and 30 patients with reactive proliferative lymphodenitis(RPL), their expression levels were compared and analyzed. The Jeko-1 cells were transfected with lentivirus contaiming PLK-1 shRNA, then the mRNA and protein expression of PLK-1 was detected by real-time guantitative PCR and Western blot nespectively, and the silencing efficacy of PLK-1 shRNA was identificd. The cell proliferation was detected by CCK method, the cell apoptosis was detected by Annexin V/PI double staining, the cell cycle was detected by PI single staining, the changes of apoptosis-related proteins BAX, BCL-2 and Caspase 3 were detected by Western blot. RESULTS: The positive expression rate of PLK-1 in tissue of MCL patients was 66.67%(28/42), which was significanfly higher than 20%(6/30) in tissue of RPL patients (P＜0.05). The PLK-1 positive expression correlated with B symptom, IPI score, Ann-Arbor stage(P＜0.05). After infection of Jeko-1 cells with lentivirus containing PLK-1 shRNA for 72 hours, the mRNA and protein expressions of PLK-1 were significantly down-regulated(P＜0.05), the proliferation rate of cells in group of PLK-1 shRNA was significanly lower than that in control and Neg shRNA groups(P＜0.05); the apoptosis rate of cells in PLK-1 shRNA group was (27.42±3.44)%, which was significantly higher than that in control group (1.23±0.42)% and Neg shRNA group (2.07±0.58) % (P＜0.05). The cell cycle analysis showed that the cell ratio in G2/M phase of PLK-1 shRNA group was (27.21±3.59) %, which was higher than that in control group (13.28±2.63)% and Neg shRNA group (14.34±2.37) %. The detection of apoptosis-related proteins showed that the expression of BAX was up-regulated, the expression of BCL-2 was down-regnlated and the expression of caspase 3 was up-regulated. CONCLUSION: The PLK-l overexpression appears in tissue of MCL patients. The silencing PLK-1 gene can inhibit the proliferation of Jeko-1 cells, induce the apopotosis of Jeko-1 cells and arrestes cell cycle in G2/M phase.

The Relationship Between MMP-2 -1306C>T and MMP-9 -1562C>T Polymorphisms and the Risk and Prognosis of T-Cell Acute Lymphoblastic Leukemia in a Chinese Population: A Case-Control Study.

BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is a malignant hematological disease and is often accompanied by a variety of genetic abnormalities. Hence, our study aims to investigate the relationship between MMP-2 -1306C>T and MMP-9 -1562C>T polymorphisms and the risk and prognosis of T-ALL. METHODS: From April 2009 to February 2011, a total of 376 T-ALL patients were chosen as the case group. Meanwhile, 352 healthy people who passed routine health examinations were selected as the control group. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to detect the frequency of MMP-2 -1306C>T (rs243865) and MMP-9 -1562C>T (rs3918242) polymorphisms in the study subjects. The serum levels of MMP-2 and MMP-9 were detected using enzyme-linked immunosorbent assay (ELISA). A Kaplan-Meier analysis was employed to analyze the event-free survival (EFS) rates of the T-All patients with different MMP-2 and MMP-9 genotypes. A multivariate COX model was applied to analyze the relationship between MMP-2 and MMP-9 polymorphisms and the prognosis of T-ALL patients. A C-statistic and net reclassification index (NRI) was carried out to evaluate the predictive value of MMP-2 and MMP-9 gene polymorphisms using the Cox model. RESULTS: Compared to the control group, the genotypic frequency of MMP-2 -1306C>T (CT + TT) and MMP-9 -1562C>T (CT + TT) in the case group was significantly higher. The serum level of MMP-9 was markedly elevated in T-ALL patients with the CT + TT genotype compared to patients with the CC genotype. The results of the Kaplan-Meier analysis showed that the median EFS was lower in T-ALL patients with the CT + TT genotype of MMP-9 -1562C>T compared to patients with the CC genotype. The results of a multivariate analysis using the Cox proportional hazard model indicated that the MMP-9 -1562C>T polymorphism was associated with the prognosis of T-ALL patients. CONCLUSION: These results indicated that MMP-2 -1306C/T and MMP-9 -1562C/T polymorphisms might be associated with an increased risk of T-ALL. The MMP-9 -1562C>T polymorphism may also be related to the prognosis of T-ALL patients.

Indole-3-Carbinol Induces Apoptosis of Hepatic Stellate Cells through K63 De-Ubiquitination of RIP1 in Rats.

BACKGROUND/AIMS: The apoptosis of activated hepatic stellate cells (HSCs) is the central event in the reversal of liver fibrosis. K63 de-ubiquitinated receptor-interacting protein (RIP)1 promotes apoptosis in tumor necrosis factor (TNF)-α signaling pathway. In the previous study, we have proved that indole-3-carbinol (I3C) could reverse different models of liver fibrosis in rats, but the mechanism is still unclear. Thus, the present research aimed to demonstrate the induction of I3C on apoptosis of HSCs and the underlying molecular mechanism. METHODS: HSC-T6, an immortalized rat liver stellate cell line, was treated for 24 hours with 25, 50 and 100 µM of I3C. The apoptosis of HSC-T6 was analyzed by flow cytometric analysis, acridine orange staining and RT-PCR, respectively. K63 de-ubiquitination of RIP1 and the expression of ubiquitin ligases and deubiquitinases were analyzed by Co-IP assay and western blot. Knockdown of deubiquitinases was undertaken by small interfering RNA (siRNA). RESULTS: The results of flow cytometric analysis indicated that the apoptotic rate of HSC-T6 was induced by I3C in a dose-dependent manner. Observation by acridine orange staining exhibited nuclear condensation and apoptotic bodies in I3C treated cells. Consistently, the expression ratio of Bax/bcl-2 was markedly increased by I3C. These results indicated that I3C could significantly induce apoptosis of HSC-T6 cells. Furthermore, Co-IP assay revealed K63 de-ubiquitination of RIP1 by I3C, associated with the induction of caspase 8. Although I3C had no effect on the expression of ubiquitin ligases cellular inhibitor of apoptosis 1/2 (cIAP1/2), the protein level of deubiquitinase cylindromatosis (CYLD) was significantly induced by I3C. Moreover, CYLD silencing reversed the pro-apoptosis induction effect of I3C and reduced the expression ratio of Bax/bcl-2 in HSC-T6 cells. CONCLUSION: These results demonstrated that I3C could induce apoptosis of HSC through RIP1 K63 de-ubiquitination by upregulating deubiquitinase CYLD.

The Transcriptome Study of Subtype M2 Acute Myeloblastic Leukemia.

Our objective is to explore the tumor-specific mutated genes by transcriptome sequencing of patients with acute myeloblastic leukemia. 96 patients with subtype M2 acute myeloid leukemia (AML), admitted during January 2007 to January 2012, were selected. Bone marrow and peripheral blood samples from the patients after the first visit and the patients who were improved or alleviated, were subjected to high-throughput sequencing to compare the gene expression. The single nucleotide mutation related to subtype M2 AML was detected. Meanwhile, real-time fluorescent quantitation RT-PCR was used to detect the AML1/ETO fusion gene and its correlation with prognosis after treatment. Among 96 patients, AML1-ETO fusion gene was positive in 52 cases, the positive rate was 54.17 %. The complete relief (CR) rate of AML1-ETO fusion gene positive patients was 84.62 %, and the CR rate of AML1/ETO fusion gene negative patients was 77.27 %; the CR rate of AML1-ETO positive patients was higher than that of patients without the fusion gene, however there was no statistical difference. In the analysis of recurrent gene mutation in AML-M2 patients, IDH2, ASXL1, TET2, JAK1 and JAK2 gene expressions were not significantly different before treatment and after CR, however, IDHI, JAK3, ABL1 and BCR gene expressions were significantly different. In the study of transcriptome in AML-M2 patients, high-throughput sequencing could effectively detect the difference of the gene expression before treatment and after CR. Furthermore, positive expression of AML1-ETO fusion gene had effect on the prognosis of patients.

[Inhibitory effect of VPA on multiple myeloma U266 cell proliferation and regulation of histone acetylation].

This study was aimed to investigate the effects of sodium valproate (VPA) on the proliferation and regulation of histone acetylation of multiple myeloma cell line U266. U266 cells were treated with VPA. Cell proliferation was determined by CCK-8 assay, and cell cycle were analyzed by flow cytometry (FCM). The expression level of HDAC1 mRNA was detected by RT-PCR, and the protein levels of HDAC1 and histone H3, H4 acetylation was detected by Western blot. The results showed that the VPA inhibited the proliferation of U266 cells in concentration-and time-dependent manners.After exposure to different concentrations of VPA for 48 hours, the proportion of G(0)/G(1) cells increased, while the proportion of S phase cells decreased. The cell cycle was arrested obviously in G(0)/G(1) phase (p < 0.05). The expression of HDAC1 mRNA was inhibited, and the protein level of HDAC1 was down-regulated, while the histone H3/H4 acetylation was up-regulated in U266 cells. It is concluded that the VPA can inhibit cell proliferation of U266 and induce G(0)/G(1) phase arrest. The increase of histone H3/H4 acetylation resulting from inhibiting HDAC1 by VPA might be considered as a possible mechanism.

[Investigation on the mechanisms of p15INK4B gene demethylation by valproate in Molt-4 cells].

OBJECTIVE: To study the antitumour effects of sodium valproate (VPA) on the proliferation, differentiation and cell cycle of Molt-4 cell and to investigate its demethylation mechanisms. METHODS: After Molt-4 cells trated with VPA at different concentrations, cell viability and growth curve were assessed by MTT assay. Cell cycle changes were analyzed by flow cytometry. The expression level of p15, DNA methyltransferase 1 (DNMT-1), DNMT3A and 3B mRNA were detected by RT-PCR and the methylation level was detected by hn-MSPCR. RESULTS: VPA significantly inhibited the proliferation of Molt-4 cells. After 48 h culture with 5.0 mmol/L VPA, the percentages of Molt-4 cells in G(0)/G(1) phase was (66.87 ± 3.31)% and in S phase was (8.47 ± 2.56)%, while in control group, the cells in G(0)/G(1) phase increased and in S phase decreased significantly. The p15 gene in Molt-4 cells failed to express due to its hypermethylation. The expression level of p15 gene mRNA increased significantly after exposure to VPA for 48 h. As compared with control group, the expression of DNMT-1 was down-regulated in a dose-dependent manner. The expression level of DNMT3B decreased at 10.0 mmol/L concentration. CONCLUSION: VPA has a demethylation effect on p15 INK4B gene by inhibiting the DNMT-1 and DNMT3B gene activities to recover p15 gene activity, which arrests Molt-4 cell in G(0)/G(1) phase.

[Synergistic effects of VPA and As2O3 on Molt-4 cells in vitro and its possible mechanisms].

This study was purposed to investigate the synergistic effects of sodium valproate (VPA) and As2O3 on the proliferation of Molt-4 cells in vitro and its possible mechanisms. Cell viability and growth curve were assessed by the MTT assay. The synergistic activity in combination of 2 drugs was determined by the Q format. The expression levels of p15, DNA methyltransferase 1 (DNMT-1), DNMT3A and DNMT 3B mRNA were detected by RT-PCR and the methylation level was detected by hn-MSPCR. The results indicated that the VPA and As2O3 both inhibited proliferation of Molt-4 cells. The combination of two drugs showed an additive effect (values of Q were>or=0.85). The inhibitory rate in combination of 5 mmol/L of VPA with 10 micromol/L of As2O3 was (70.31+/-2.54)%. The p15 gene in Molt-4 cell line failed to express due to its hypermethylation. The level of p15 gene mRNA expression increased significantly after exposure to VPA in combination with As2O3 for 48 h. As compared with control group, the expression of DNMT-1 was down-regulated in a dose-dependent manner, whereas DNMT3A had no significant differences from the control. The level of expression of DNMT3B seemed to decrease at 10 mmol/L concentration. There were significant differences between the combination of the two drugs and the control group. The gray value of methylated bands decreased after the treatment of VPA alone and in combination with As2O3 in a dose-dependent manner. It is concluded that VPA induces demethylation of p15 INK4B gene by inhibiting the DNMT-1 and DNMT3B gene activities, which up-regulates the p15 gene, recovers its activity. The combination of VPA with As2O3 has the synergistic additive effect on the inhibition of cell viability, so that VPA can reduce the side effect of As2O3 on liver function, which would be verified in the clinical practice.