IL-17 induces NSCLC cell migration and invasion by elevating MMP19 gene transcription and expression through the interaction of p300-dependent STAT3-K631 acetylation and its Y705-phosphorylation

The cancer cell metastasis is a major death reason for patients with non-small cell lung cancer(NSCLC).Although researchers have disclosed that interleukin 17(IL-17)can increase matrix metalloproteinases(MMPs)induction causing NSCLC cell metastasis,the underlying mechanism remains unclear.In the study,we found that IL-17 receptor A(IL-17RA),p300,p-STAT3,Ack-STAT3,and MMP19 were up-regulated both in NSCLC tissues and NSCLC cells stimulated with IL-17.p300,STAT3 and MMP19 overexpression or knockdown could raise or reduce IL-17-induced p-STAT3,Ack-STAT3 and MMP19 level as well as the cell migration and invasion.Mechanism investigation revealed that STAT3 and p300 bound to the same region(−544 to−389 nt)of MMP19 promoter,and p300 could acetylate STAT3-K631 elevating STAT3 transcriptional activity,p-STAT3 or MMP19 expression and the cell mobility exposed to IL-17.Meanwhile,p300-mediated STAT3-K631 acetylation and its Y705-phosphorylation could interact,synergistically facilitating MMP19 gene transcription and enhancing cell migration and invasion.Besides,the animal experiments exhibited that the nude mice inoculated with NSCLC cells by silencing p300,STAT3 or MMP19 gene plus IL-17 treatment,the nodule number,and MMP19,Ack-STAT3,or p-STAT3 production in the lung metastatic nodules were all alleviated.Collectively,these outcomes uncover that IL-17-triggered NSCLC metastasis involves up-regulating MMP19 expression via the interaction of STAT3-K631 acetylation by p300 and its Y705-phosphorylation,which provides a new mechanistic insight and potential strategy for NSCLC metastasis and therapy.

A novel isoxazole compound CM2-II-173 inhibits the invasivephenotype of triple-negative breast cancer cells

Invasion and metastasis are important hallmarks of breast cancer and are the leading cause of patient mortality.Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer characterized by a poor prognosis and a lackof effective targeted therapies. The present study investigated the inhibitory effect of a novel FTY720 derivative on theinvasive phenotype of TNBC cells. Here, we showed that a novel compound with an isoxazole ring, 4-(3-Decylisoxazol-5-yl)-1-hydroxy-2-(hydroxymethyl)butan-2-aminium chloride (CM2-II-173), significantly inhibitedinvasiveness of MDA-MB-231 TNBC cells. Expression of matrix metalloproteinase (MMP)-9 and invasiveness ofMCF10A normal breast cells induced by sphingosine-1-phosphate (S1P) were reduced by CM2-II-173 treatment.Activations of pMEK1, pAkt, pERK, and p38 MAPK by S1P were inhibited by treatment with CM2-II-173.Proliferation and anchorage-independent growth of MDA-MB-231 TNBC cells were significantly decreased by CM2-II-173. CM2-II-173 efficiently induced apoptosis in MDA-MB-231 TNBC cells. CM2-II-173 significantly inhibitedinvasive phenotypes of breast, liver, prostate, and ovarian cancer cells. CM2-II-173 exhibited a more potent effect onthe invasiveness of MDA-MB-231 TNBC cells compared to FTY720. Taken together, this study demonstrated thatCM2-II-173 has the potential to be a lead compound that can inhibit cancer progression of not only TNBC cells, butalso of liver, prostate, and ovarian cancer cells.

IN VIVO COMPARATIVE OBSERVATION ON THE INVASIVENESS OF VARIOUS ORGANS BY DIFFERENT LEUKEMIA CELLS

Using patho-morphological method and transplantation bio-assay, the in vivo invasiveness of leukemia cells is three transplantable mouse T cell leukemia models was comparatively studied. The results showed that the invasion to the liver was consistent, but that to other organs was obviously different. L615 and L7212 leukemia cells preferred to the bone marrow and spleen than to the peritoneum while L7811 leukemia cells were just the opposite. Transplantation bio-assay demonstrated that leukemia cells were present in the bone marrow of L615 mice as early as 6 hours after leukemic cell inoculation, but no leukemia cells was detected in bone marrow of L7811 mice 2 days after inoculation. In the terminal phase, L615 mice bone marrow became filled with leukemia cells, but L7811 mice bone marrow contained only a few leukemia cells. The difference of invasiveness of leukemia cells among organs is probably related to "homing" receptor. The same type of leukemia cells may possess multiple "homing" receptor.

Vibramycin inhibits the expression of MMP-2 and the invasiveness of PC-3 cells in vitro

Objective To study the inhibition of vibramycin on the expression of matrix metalloproteinase-2 (MMP-2) and the invasiveness of androgen-independent prostatic carcinoma cell line PC - 3 in vitro. Methods Immunohistochemistry stain and transwell chamber were used to investigate the expression of MMP-2 in different concentration of vibramycin treated PC-3 cells and the invasive ability of different concentration of vibramycin treated PC-3 cell. Results The positive rate of MMP-2 inJune 2003 Vol12 No2 PC-3 cells was decreased at a concentration of 5 mg/L of vibramycin and decreased dramatically at the concentration of 10 mg/L. The cells moved throuth the membrane was(82. 0 ± 4.6)/field in the control group, while decreased to(26.1 ±3.6),(7.2 ±2.2) and(3.3± 0.7)/field in 5,10 and 20 mg/L vibramycin treated PC-3 cell respectively. Conclusion Vibramycin can inhibit the invasiveness and metastatasis of PC-3 cells, the mechanism of which is related to the inhibition of MMP-2 in PC-3 cell.10refs.

PBX3 promotes migration and invasion of colorectal cancer cells via activation of MAPK/ERK signaling pathway

AIM: To investigate the role of pre-B-cell leukemia homeobox (PBX)3 in migration and invasion of colorectal cancer (CRC) cells.

ANGPTL2 expression in gastric cancer tissues and cells and its biological behavior

AIM To explore expression of angiopoietin-like protein 2(ANGpT L2) and its effect on biological behavior such as proliferation and invasiveness in gastric cancer. METHODS Western blotting was used to detect expression of ANGp TL2 in 60 human normal gastric tissues, 60 human gastric cancer tissues and gastric cell lines including GES-1, N87, SGC7901, BGC823 and pA MC82. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) and Transwell assay were used to detect the proliferation and invasive ability of gastric cancer cells. RESULTS Compared to normal tissues, ANGp TL2 protein levels were significantly upregulated in gastric tissues, and this level was closely correlated with gastric tumor grade, clinical stage and lymph node metastasis. Compared to GES-1 cells, ANGpT L2 mR NA and protein levels were significantly increased in gastric cancer cells including N87, SGC7901, BGC823 and p AMC82. The expression of ANGpT L2 in highly malignant gastric cancer cell lines BGC823 and pA MC82 was significantly higher than in low malignancy gastric cancer cell lines N87 and SGC7901. MTT and Transwell experiments indicated that the proliferation rate and invasive ability of stable overexpressed gastric cancer cells was faster than in cells transfected with Lv-NC and blank controlcells, and the invasive ability of stable overexpressed gastric cancer cells was higher than that of cells transfected with Lv-NC and blank control cells.CONCLUSION ANGp TL2 contributed to proliferation and invasion of gastric cancer cells. In clinical treatment, ANGpT L2 may become a new target for treatment of gastric cancer.

MicroRNA-mediated Silencing of RhoC Inhibits Tumor Invasion and Increases Chemosensitivity to Paclitaxel in SKOV3 Cells in vitro

RhoC is a member of the Ras-homologous family of genes which are implicated in tumorigenesis and tumor progression. Up-regulation of RhoC is associated with tumor progression in ovarian carcinoma and RhoC is significantly correlated with the invasive capability of ovarian cancer cell lines in vitro, We developed a system that blocks RhoC in the human ovarian cancer SKOV3 cells using specific MicroRNA（miRNA） interference. By transfecting SKOV3 cells with the plasmid vector to express specific MiRNA that targets human RhoC, we were able to establish a stable clone in which RhoC expression was significantly downregulated. This resulted in the decreased invasive potential of SKOV3 cells as well as increased chemosensitivity to paclitaxel. RhoC involves in invasion and chemosensitivity of SKOV3, indicating that RhoC may be a promising therapeutic target for ovarian cancer.

lncRNACNN3-206 activates intestinal epithelial cell apoptosis and invasion by sponging miR-212, an implication for Crohn’s disease

BACKGROUND Statistics indicate that the incidence of Crohn’s disease(CD)is rising in many countries.The poor understanding on the pathological mechanism has limited the development of effective therapy against this disease.Previous studies showed that long noncoding RNAs(lncRNAs)could be involved in autoimmune diseases including CD,but the detailed molecular mechanisms remain unclear.AIM To identify the differentially expressed lncRNAs in the intestinal mucosa associated with CD,and to characterize their pathogenic role(s)and related mechanisms.METHODS The differential expression of lncRNAs was screened by high-throughput RNA sequencing,and the top candidate genes were validated in an expanded cohort by real-time PCR.The regulatory network was predicted by bioinformatic software and competitive endogenous RNA analysis,and was characterized in Caco-2 and HT-29 cell culture using methods of cell transfection,real-time PCR,Western blotting analysis,flow cytometry,and cell migration and invasion assays.Finally,these findings were confirmed in vivo using a CD animal model.RESULTS The 3'end of lncRNACNN3-206 and the 3’UTR of Caspase10 contain highaffinity miR212 binding sites.lncRNACNN3-206 expression was found to be significantly increased in intestinal lesions of CD patients.Activation of the lncRNACNN3-206-miR-212-Caspase10 regulatory network led to increased apoptosis,migration and invasion in intestinal epithelial cells.Knockdown of lncRNACNN3-206 expression alleviated intestinal mucosal inflammation and tissue damage in the CD mouse model.CONCLUSION lncRNACNN3-206 may play a key role in CD pathogenesis.lncRNACNN3-206 could be a therapeutic target for CD treatment.

Phagocytic Uptake of Nosema bombycis (Microsporidia) Spores by Insect Cell Lines

Microsporidia are highly specialized obligate intracellular parasites that can infect a wide variety of animals ranging from protists to mammals. The classical concept of the parasite invasion into a host cell involves its polar tube acting as a needle-syringe system. However, recent studies show microsporidian spores can also gain access to host cells by phagocytosis. The present study investigated the phagocytic uptake process of causative agent of the pebrine disease, Nosema bombycis, in several insect cell lines. We observed KOH-treated spores and cold-storaged spores can be easily uptaken by all the studied cell types 4 h post inoculation. In contrast, large numbers of freshly recovered spores remained in the culture medium. To further investigate the intracellular fates of KOH-treated spores and cold-storaged spores, electron and fluorescence microscopy were performed. No intracellular germination or subsequent parasite development were observed. Intracellular spores can be detected in host cells by polyclonal antibody 7 d post inoculation, suggesting phagocytized N. bombycis could not be digested by these non-professional phagocytes. Our results suggest that, phagocytic uptake of N. bombycis spores might represent a defense mechanism of the host cells and the intact spore wall barrier enable freshly recovered spores to keep resistance to this mechanism.

Disruption of colonic barrier function and induction of mediator release by strains of Campylobacter jejuni that invade epithelial cells

AIM: To study the mechanisms by which Campylobacter jejuni (C. jejuni) causes inflammation and diarrhea. In particular, direct interactions with intestinal epithelial cells and effects on barrier function are poorly under- stood. METHODS: To model the initial pathogenic effects of C. jejuni on intestinal epithelium, polarized human colonic HCA-7 monolayers were grown on permeabilized filters and infected apically with clinical isolates of C. jejuni. Integrity of the monolayer was monitored by changes in monolayer resistance, release of lactate dehydrogenase, mannitol fluxes and electron microscopy. Invasion of HCA-7 cells was assessed by a modified gentamicin protection assay, translocation by counting colony forming units in the basal chamber, stimulation of mediator release by immunoassays and secretory responses in monolayers stimulated by bradykinin in an Ussing chamber. RESULTS: All strains translocated across monolayers but only a minority invaded HCA-7 cells. Strains that invaded HCA-7 cells destroyed monolayer resistance over 6 h, accompanied by increased release of lactate dehydrogenase, a four-fold increase in permeability to [3H] mannitol, and ultrastructural disruption of tight junctions, with rounding and lifting of cells off the filter membrane. Synthesis of interleukin (IL)-8 and prostaglandin E2 was increased with strains that invaded the monolayer but not with those that did not. CONCLUSION: These data demonstrate two distinct effects of C. jejuni on colonic epithelial cells and provide an informative model for further investigation of initial host cell responses to C. jejuni.

Exposure to environmental bisphenol A inhibits HTR-8/SVneo cell migration and invasion

Environmental pollutants,such as bisphenol A(BPA) have recently been implicated in the development of adverse birth outcomes.However,the underlying teratogenic mechanisms remain unclear.We investigated the effects of BPA on the migration and invasion of human primary extravillous trophoblast HTR-8/SVneo cells.Our results indicated that BPA reduced cell migration and invasion.Moreover,it altered the ratio of matrix metalloproteinases(MMPs) and tissue inhibitors of MMPs(TIMPs) by downregulating MMP-2 and MMP-9,and upregulating TIMP-1 and TIMP-2.Furthermore,BPA suppressed integrin β1,integrin α5,and vimentin.Interestingly,BPA-induced invasion was partially restored by G15,a membrane G-protein-coupled estrogen receptor 30 antagonist.We further revealed that 42 proteins were differentially expressed by mass spectrometry analysis,which could be divided into three categories based on gene ontology including biological process,cellular component,and molecular function.These results suggest that BPA reduces HTR-8/SVneo cell migration and invasion by downregulating MMP-2 and MMP-9,up-regulating TIMP-1 and TIMP-2,and suppressing adhesion molecules.

Catechu Inhibiting Cathepsin B Activity and Motility of HT1080 Cells

We reported that Catechu extract has a significant inhibitory effect on cathepsin B activity. The IC50 value for the Catechu extract against cathepsin B was 7.6 μg/mL. In addition, we showed that HT1080 human fibrosarcoma cells express cathepsin B and Catechu modulate the invasion and motility of these cells. These data may provide molecular mechanisms for the therapeutic effects of Catechu.

A 3D biophysical model for cancer spheroid cell-enhanced invasion in collagen-oriented fiber microenvironment

The process of in situ tumors developing into malignant tumors and exhibiting invasive behavior is extremely complicated.From a biophysical point of view,it is a phase change process affected by many factors,including cell-to-cell,cell-to-chemical material,cell-to-environment interaction,etc.In this study,we constructed spheroids based on green fluorescence metastatic breast cancer cells MDA-MB-231 to simulate malignant tumors in vitro,while constructed a three-dimensional(3D)biochip to simulate a micro-environment for the growth and invasion of spheroids.In the experiment,the 3D spheroid was implanted into the chip,and the oriented collagen fibers controlled by collagen concentration and injection rate could guide the MDA-MB-231 cells in the spheroid to undergo directional invasion.The experiment showed that the oriented fibers greatly accelerated the invasion speed of MDA-MB-231 cells compared with the traditional uniform tumor micro-environment,namely obvious invasive branches appeared on the spheroids within 24 hours.In order to analyze this interesting phenomenon,we have developed a quantitative analyzing approach to explore strong angle correlation between the orientation of collagen fibers and invasive direction of cancer cell.The results showed that the oriented collagen fibers produced by the chip can greatly stimulate the invasion potential of cancer cells.This biochip is not only conducive to modeling cancer cell metastasis and studying cell invasion mechanisms,but also has the potential to build a quantitative evaluation platform that can be used in future chemical drug treatments.

KIFC3 promotes proliferation, migration and invasion of esophageal squamous cell carcinoma cells by activating EMT and β-catenin signaling

BACKGROUND Esophageal squamous cell carcinoma(ESCC)is one of the most common malignancies.A total of 45 kinesin superfamily proteins(KIFs)have been identified in humans,among which several family members have demonstrated varied functions in tumor pathobiology via different mechanisms,including regulation of cell cycle progression and metastasis.KIFC3 has microtubule motor activity and is involved in cancer cell invasion and migration,as well as survival.However,the role of KIFC3 in ESCC is still unknown.AIM To evaluate the role of KIFC3 in ESCC and the underlying mechanisms.METHODS Expression of KIFC3 was evaluated in ESCC tissues and adjacent normal esophageal tissues.The prognostic value of KIFC3 was analyzed using Kaplan-Meier Plotter.Colony formation,EdU assays,cell cycle analysis,Transwell assay,immunofluorescence,and western blotting were performed in ESCC cell lines after transfection with pLVX-Puro-KIFC3-shRNA-and pLVX-Puro-KIFC3-expressing lentiviruses.A xenograft tumor model in nude mice was used to evaluate the role of KIFC3 in tumorigenesis.Inhibitor ofβ-catenin,XAV-939,was used to clarify the mechanism of KIFC3 in ESCC.To analyze the differences between groups,t test and nonparametric tests were used.P<0.05 was considered statistically significant.RESULTS Immunohistochemical staining indicated that KIFC3 was upregulated in ESCC tissues compared with adjacent normal tissues.Kaplan-Meier Plotter revealed that overexpressed KIFC3 was associated with poor prognosis in ESCC patients.Colony formation and EdU assay showed that KIFC3 overexpression promoted cell proliferation,while KIFC3 knockdown inhibited cell proliferation in ESCC cell lines.In addition,cell cycle analysis showed that KIFC3 overexpression promoted cell cycle progression.KIFC3 knockdown suppressed ESCC tumorigenesis in vivo.Transwell assay and western blotting revealed that KIFC3 overexpression promoted cell migration and invasion,as well as epithelial-mesenchymal transition(EMT),while KIFC3 knockdown showed the opposite results.Mechanistically,KIFC3 overexpression promoted β-catenin signaling in KYSE450 cells;however,the role of KIFC3 was abolished by XAV-939,the inhibitor of β-catenin signaling.CONCLUSION KIFC3 was overexpressed in ESCC and was associated with poor prognosis.Furthermore,KIFC3 promoted proliferation,migration and invasion of ESCC via β-catenin signaling and EMT.

Mechanism of SNHG12 in Regulating Human Angiostatin Binding Protein Through MicroRNA497 in the Migration and Invasion of Human Lung Cancer Cells

Objective:To investigate the effect of small nucleolar host gene 12(SNHG12)on the migration and invasion of human lung cancer cells by regulating human angiostatin binding protein through microribonucleic acid(microRNA)-497.Methods:A549,H1299,and PC9 cells were cultured in Roswell Park Memorial Institute(RPMI)-1640 medium containing 10%fetal bovine serum,and human bronchial epithelial(HBE)cells were cultured in Dulbecco’s modified eagle medium(DMEM)containing 10%fetal bovine serum.The incubator conditions were as follows:saturated humidity,37℃,and 5%carbon dioxide(CO2).Results:The gene expressions of small nucleolar host gene 12(SNHG12)in HBE,A549,H1299,and PC9 were 1.00±0.02,5.61±0.42,3.78±0.29,and 3.51±0.23,respectively.The gene expressions of microRNA-497HBE,A549,H1299,and PC9 were 1.00±0.13,0.21±0.04,0.35±0.05,and 0.37±0.06,respectively,with P<0.05.The microRNA-497 gene expression and cell apoptosis rate in the microRNA-497 group and the microRNA-497+pcDNA3.1 group were significantly higher than those in the miR-NC group,whereas the A value and cell invasion number were significantly lower than those in the miR-negative control(NC)group,with P<0.05.Compared with the microRNA-497+pcDNA3.1 group,the microRNA-497 gene expression and cell apoptosis rate in the microRNA-497+SNHG12 group were significantly lower,whereas the A value and cell invasion number were significantly higher,with P<0.05.Conclusion:SNHG12 can inhibit the migration and invasion of human lung cancer cells by regulating human angiostatin binding protein through microRNA-497.

PATHOLOGICAL STUDIES ON THE ANTI－INVASIVE CHARACTER BY RECOMBINANT HUMAN INTERLEUKIN－6 GENE－TRANSFECTED MOUSE LEUKEMIA CELLS

Mouse FBL-3 erythroleukemia cells were transfected with recombinant human interleukin-6 (rhIL-6) gene and a clone secreting IL-6 was selected (i.e., FBL-3-IL-6+). The cell clone secreting IL-6 was inoculated into C57BL/6 mouse. The growth of tumors was observed and histologic analyses of the tumors in situ, liver, spleen and bone marrow were performed after inoculation. The mice inoculated with wild-type FBL-3 erythroleukemia cells were used as the control. The results showed that the later the tumor occurrence, the slower the tumor development,the lower the pathological changes degree and the longer the survival time in experimental group compared to that of the control. The results demonstrated that the inoculation of the FBL-3 cell clone secreting IL-6 can inhibit the invasion of leukemia cells, suggesting that the FBL-3-IL-6+ cells can he used as a vaccine to treat leukemia.

Anal Invasive Squamous Cell Cancer and Human Papillomavirus Distribution in HIV-Infected and Non-HIV-Infected Individuals

Invasive-squamous-cell-cancer (ISCC) of the anal canal is an uncommon disease. Human papillomavirus (HPV) is the etiological agent of most of types of ISCC. The incidence of ISCC has been increasing in HIV-infected individuals, even after the introduction of highly active antiretroviral therapy. The aim of this study was to analyze biopsy specimens from patients diagnosed with ISCC at a tertiary hospital from 1983 to 2012 in order to detect HPV-DNA. Methods: Formaldehyde-fixed, paraffin-embedded specimens from patients with ISCC underwent HPV-DNA genotyping using multiplex PCR assay. Results: A total of 31 cases were collected;10 were HIV-infected (9 men, 1 woman) and 21 non-HIV-infected (11 men, 10 women). HPV infection was detected in 87.5% (7/8) of the HIV-infected patients (DNA from 2 biopsies was degraded) and 76.2% (16/21) of non-HIV-infected individuals. Multiple-type infections were only found in 28.6% (2/7) of the HIV-infected patients (no multiple-type infections in non-HIV-infected individuals). The most prevalent type was HPV-16: 50% (4/8) in the HIV-infected group (57% [4/7] of the HPV-positive samples) and 66.7% (14/21) in the non-HIV-infected group (87.5% (14/16) of the HPV-positive samples). Remarkably, 37.5% (3/8) of the HIV-infected group had high-risk HPV types not included in the vaccines (HPV-33, 51, 52, and 66) compared with 4.8% in the non-HIV-infected group (1/21, HPV-52). All cases of anal ISCC in HIV-infected patients were recorded in the highly active antiretroviral therapy era. Conclusion: HIV-infected patients presented anal ISCC with a higher proportion of high-risk HPV types not covered by the conventional vaccines than non-HIV-infected individuals.

Research on the effects of PIAS3 expression on the invasion of glioma TJ905 cells

Objective To investigate the function and possible mechanisms of PIAS3 expression on the invasion of TJ905 cells. Methods PIAS3 overexpression vectors were constructed and PIAS3 siRNA were chemically synthesized, which were separately transfected into TJ905 cells for upregulation or

Effect of hypoxia-inducible factor-1α on proliferation and invasion of prostate cancer PC-3 cell in hypoxic situation

Objective We transfected recombinant expression plasmid of pcDNA3. 1-HIF-1α into prostate cancer cells, to research effect of HIF-1α on proliferation of prostate cancer cell PC-3. Methods We selected a stable expression cell line with G418 we selected by transfection

Effect of Down-regulation of MMP-2 by Quercetin on the Migration and Invasion of Uterine Fibroids Cells through the cAMP Signaling Pathway

Objective:To investigate the effect of down-regulation of matrix metalloproteinase-2(MMP-2)by down-regulating the cyclic adenosine monophosphate(cAMP)signaling pathway on the migration and invasion of uterine fibroids cells.Methods:A total of 65 female SD rats were randomly divided into five groups after being adaptively fed for 7 d.Except for the blank group,the remaining four groups of rats were injected with 0.05 mg/(100 g·d)estradiol benzoate and 0.5 mg/(100g·d)progesterone into the muscle to establish a uterine fibroids rat model.After successful modeling,the blank group and model group were given 200 mg/(kg·d)physiological saline by gavage,the low-dose group was given 100 mg/(kg·d)mifepristone by gavage,the medium-dose group was given 200 mg/(kg·d)mifepristone by gavage,and the high-dose group was given 300 mg/(kg·d)mifepristone by gavage.After continuous gavage treatment for 21 d,serum and uterine tissues were collected from rats to observe and compare the expression levels of MMP-2 mRNA,TIMP-2 mRNA,estradiol(E2),cAMP signaling pathway related proteins,and the migration and invasive ability of uterine fibroids cells in the five groups of rats.Results:The expression levels of MMP-2 mRNA and E2in the high-dose group were lower than those in the low-dose group and the medium-dose group,and the expression level of TIMP-2 mRNA was higher than that in the low-dose group and the medium-dose group(P<0.05).The number of cell migration in a single visual field of rats in the high-dose group was lower than that in the low-dose group and the medium-dose group(P<0.05).The number of cell invasion in a single visual field of rats in the high-dose group was lower than that in the low-dose group and the medium-dose group(P<0.05).The mRNA expression levels of cAMP,PDE and PK in the high-dose group were higher than those in the low-dose group,and the mRNA expression levels of AC in the high-dose group were lower than those in the low-dose group(P<0.05).The mRNA expression levels of cAMP and PDE in the high-dose group were higher than those in the mediumdose group(P<0.05).Conclusion:Letrozole may down-regulate the expression level of MMP-2 through the cAMP signaling pathway to inhibit the migration and invasion of uterine fibroids cells.With increasing doses of letrozole,its inhibitory effect on the migration and invasion of uterine fibroids cells will be enhanced.However,the optimal dosage of letrozole for inhibiting the migration and invasion of uterine fibroids cells is yet to be determined.