Exosomes derived from pancreatic cancer cells induce activation and profibrogenic activities in pancreatic stellate cells

Pancreatic cancer cells (PCCs) interact with pancreatic stellate cells (PSCs), which play a pivotal role in pancreatic fibrogenesis, to develop the cancer-conditioned tumor microenvironment. Exosomes are membrane-enclosed nanovesicles, and have been increasingly recognized as important mediators of cell-to-cell communications. The aim of this study was to clarify the effects of PCC-derived exosomes on cell functions in PSCs. Exosomes were isolated from the conditioned medium of Panc-1 and SUIT-2 PCCs. Human primary PSCs were treated with PCC-derived exosomes. PCC-derived exosomes stimulated the proliferation, migration, activation of ERK and Akt, the mRNA expression of α-smooth muscle actin (ACTA2) and fibrosis-related genes, and procollagen type I C-peptide production in PSCs. Ingenuity pathway analysis of the microarray data identified transforming growth factor β1 and tumor necrosis factor as top upstream regulators. PCCs increased the expression of miR-1246 and miR-1290, abundantly contained in PCC-derived exosomes, in PSCs. Overexpression of miR-1290 induced the expression of ACTA2 and fibrosis-related genes in PSCs. In conclusion, PCC-derived exosomes stimulate activation and profibrogenic activities in PSCs. Exosome-mediated interactions between PSCs and PCCs might play a role in the development of the tumor microenvironment.     

Exosomes derived from human mesenchymal stem cells confer drug resistance in gastric cancer

Mesenchymal stem cells (MSCs) play an important role in chemoresistance. Exosomes have been reported to modify cellular phenotype and function by mediating cell-cell communication. In this study, we aimed to investigate whether exosomes derived from MSCs (MSC-exosomes) are involved in mediating the resistance to chemotherapy in gastric cancer and to explore the underlying molecular mechanism. We found that MSC-exosomes significantly induced the resistance of gastric cancer cells to 5-fluorouracil both in vivo and ex vivo. MSC-exosomes antagonized 5-fluorouracil-induced apoptosis and enhanced the expression of multi-drug resistance associated proteins, including MDR, MRP and LRP. Mechanistically, MSC-exosomes triggered the activation of calcium/calmodulin-dependent protein kinases (CaM-Ks) and Raf/MEK/ERK kinase cascade in gastric cancer cells. Blocking the CaM-Ks/Raf/MEK/ERK pathway inhibited the promoting role of MSC-exosomes in chemoresistance. Collectively, MSC-exosomes could induce drug resistance in gastric cancer cells by activating CaM-Ks/Raf/MEK/ERK pathway. Our findings suggest that MSC-exosomes have profound effects on modifying gastric cancer cells in the development of drug resistance. Targeting the interaction between MSC-exosomes and cancer cells may help improve the efficacy of chemotherapy in gastric cancer.     

Human umbilical cord blood-derived mesenchymal stem cells ameliorate psoriasis-like skin inflammation in mice

Mesenchymal stem cells (MSCs) inhibit the proliferation or activation of lymphocytes, and their inhibitory effects do not require human leukocyte antigen (HLA)-matching because MSCs express low levels of HLA molecules. Therefore, MSCs may be able to regulate immune responses. In this study, we determined whether MSCs could inhibit psoriasis-like skin inflammation in mice. After induction of psoriasis-like skin inflammation using intradermal injection of IL-23 or topical application of imiquimod with or without treatment with MSC, mouse skins were collected, and H&E staining and real-time PCR were performed. IL-23-induced skin inflammation was inhibited when MSCs were injected on day ?1 and day 7. The expression of proinflammatory cytokines such as IL-6, IL-17, and TNF-α was inhibited by MSC injection, and the expression of chemokines such as CCL17, CCL20, and CCL27 was also decreased in mouse skin. We also determined whether MSCs could not only prevent but also treat psoriasis-like skin inflammation in mice. Furthermore, in vitro experiments also showed anti-inflammatory effects of MSCs. Dendritic cells which are co-cultured with MSCs suppressed CD4+ T cell activation and differentiation, which are important for the pathogenesis of psoriasis. These results suggest that MSCs could be useful for treating psoriasis.     

Gefitinib inhibits the cross‐talk between mesenchymal stem cells and prostate cancer cells leading to tumor cell proliferation and inhibition of docetaxel activity

Increasing evidence suggests that bone marrow derived mesenchymal stem cells (BM‐MSCs) are recruited into the stroma of developing tumors where they contribute to progression by enhancing tumor growth and metastasis, or by inducing anticancer‐drug resistance. Prostate cancer cells secrete ligands of epidermal growth factor receptor (EGFR) and EGFR signaling could play an important role in the cross‐talk between mesenchymal stem cells and prostate cancer cells. In this study, we showed that treatment of human primary MSCs with conditioned medium (CM) derived from the bone metastatic PC3 carcinoma cells (PC3‐CM) resulted in: a significant activation of EGFR; increased proliferation; increased osteoblastic but decreased adipocitic differentiation; inhibition of senescence induced by serum starvation; increased CCL5 secretion. These activities were significantly inhibited in the presence of the EGFR tyrosine kinase inhibitor gefitinib. PC3‐CM directly inhibited osteoclastogenesis as well as the ability of osteoblasts to induce osteoclast differentiation. The increased MSCs migration by PC3‐CM and PC3 cells was partially mediated by CCL5. MSC‐CM increased the formation of colonies by PC3 cells and inhibited the anti‐proliferative activity of Docetaxel. Activation of EGFR expressed on MSCs by PC3‐CM enhanced their capability to increase PC3 cells proliferation and to inhibit Docetaxel activity. These findings, by showing that the tumor‐promoting interactions between PC3 cells and MSCs are mediated, at least in part, by EGFR, suggest a novel application of the EGFR‐tyrosine kinase inhibitors in the treatment of prostate cancer. J. Cell. Biochem. 114: 1135–1144, 2013. © 2012 Wiley Periodicals, Inc.     

Targeting autophagy blocks melanoma growth by bringing natural killer cells to the tumor battlefield

Solid tumors are able to establish and sustain an immune suppressive microenvironment, which prevents the infiltration of cytotoxic effector immune cells into the tumor bed. We showed that genetic targeting of the macroautophagy/autophagy gene Becn1/Beclin1 in B16-F10 tumors inhibits their growth by inducing a massive infiltration of functional natural killer (NK) cells into the tumor bed. Such infiltration is primarily due to the ability of BECN1-defective tumor cells to overexpress and release CCL5 cytokine in the tumor microenvironment by a mechanism involving the activation of the MAPK8/JNK-JUN/c-Jun signaling pathway. Clinically, we reported a strong positive correlation between the expression of NK cell marker and CCL5 in human melanoma tumors and more importantly, a significant increased survival is found in melanoma patients expressing a high level of CCL5. Overall, these findings highlight the impact of targeting autophagy in breaking the immunosuppressive tumor microenvironment barrier, thus allowing the trafficking of cytotoxic NK cells into the tumor bed. This study underscore the importance of autophagy inhibition in tumors as a novel therapeutic strategy to fully exploit NK cells antitumor properties in clinical settings.     

Regulated genes in mesenchymal stem cells and gastric cancer

AIM: To investigate the genes regulated in mesenchymal stem cells(MSCs) and diffuse-type gastric cancer(GC),gene expression was analyzed. METHODS: Gene expression of MSCs and diffuse-type GC cells were analyzed by microarray. Genes related to stem cells, cancer and the epithelial-mesenchymal transition(EMT) were extracted from human gene lists using Gene Ontology and reference information. Gene panels were generated, and messenger RNA gene expression in MSCs and diffuse-type GC cells was analyzed. Cluster analysis was performed using the NCSS software.RESULTS: The gene expression of regulator of G-protein signaling 1(RGS1) was up-regulated in diffuse-type GC cells compared with MSCs. A panel of stem-cell related genes and genes involved in cancer or the EMT were examined. Stem-cell related genes, such as growth arrest-specific 6, musashi RNA-binding protein 2 and hairy and enhancer of split 1(Drosophila), NOTCH family genes and Notch ligands, such as delta-like 1(Drosophila) and Jagged 2, were regulated.CONCLUSION: Expression of RGS1 is up-regulated, and genes related to stem cells and NOTCH signaling are altered in diffuse-type GC compared with MSCs.     

Macrophage-associated mesenchymal stem cells assume an activated, migratory, pro-inflammatory phenotype with increased IL-6 and CXCL10 secretion

Mesenchymal stem cells (MSCs) exhibit tropism for sites of tissue injury and tumors. However, the influence of the microenvironment on MSC phenotype and localization remains incompletely characterized. In this study, we begin to define a macrophage-induced MSC phenotype. These MSCs secrete interleukin-6 (IL-6), CCL5, and interferon gamma-induced protein-10 (CXCL10) and exhibit increased mobility in response to multiple soluble factors produced by macrophages including IL-8, CCL2, and CCL5. The pro-migratory phenotype is dependent on activation of a c-Jun N-terminal kinase (JNK) pathway. This work begins to identify the influence of macrophages on MSC biology. These interactions are likely to play an important role in the tissue inflammatory response and may provide insight into the migratory potential of MSCs in inflammation and tissue injury.     

Lysophosphatidic acid in malignant ascites stimulates migration of human mesenchymal stem cells

Lysophosphatidic acid (LPA) is elevated in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests a pivotal role of mesenchymal stem cells (MSCs) or stromal cells in tumorigenesis. In the present study, we demonstrated that ascites from ovarian cancer patients and LPA increased migration of human MSCs. The migration of MSCs induced by LPA and malignant ascites was completely abrogated by pretreatment with Ki16425, an antagonist of LPA receptors, and by silencing of endogenous LPA(1), but not LPA(2), with small interference RNA, suggesting a key role of LPA played in the malignant ascites-induced migration. LPA induced activation of ERK through pertussis toxin-sensitive manner, and pretreatment of MSCs with U0126, a MEK inhibitor, or pertussis toxin attenuated the LPA-induced migration. Moreover, LPA induced activation of RhoA in MSCs, and pretreatment of the cells with Y27632, a Rho kinase inhibitor, markedly inhibited the LPA-induced migration. In addition, LPA and malignant ascites increased intracellular concentration of calcium in MSCs, and Ki16425 completely inhibited the elevation of intracellular calcium. These results suggest that LPA is a crucial component of the malignant ascites which induce the migration of MSCs and elevation of intracellular calcium.     

The effects of adipose-derived stem cells on CD133-expressing bladder cancer cells

Mesenchymal stem cells (MSCs) hold great promise as therapeutic agents in regenerative medicine. They are also considered as a preferred cell source for urinary tract reconstruction. However, as MSCs exhibit affinity to tumor microenvironment, possible activation of tumor-initiating cells remains a major concern in the application of stem cell-based therapies for patients with a bladder cancer history. To analyze the influence of adipose-derived stem cells (ASCs) on bladder cancer cells with stem cell-like properties, we isolated CD133-positive bladder cancer cells and cultured them in conditioned medium from ASCs (ASC-CM). Our results showed that parental 5637 and HB-CLS-1 cells showed induced clonogenic potential when cultured in ASC-CM. Soluble mediators secreted by ASCs increased proliferation and viability of unsorted cells as well as CD133+ and CD133− subpopulations. Furthermore, incubation with ASC-CM modulated activation of intracellular signaling pathways. Soluble mediators secreted by ASCs increased phosphorylation of AKT1/2/3 (1.4-fold, P < 0.05), ERK1/2 (1.6-fold, P < 0.02), and p70 S6K (1.4-fold) in CD133+ cells isolated from 5637 cell line. In turn, decreased phosphorylation of those three proteins involved in PI3K/Akt and MAPK signaling was observed in CD133+ cells isolated from HB-CLS-1 cell line. Our results revealed that bladder cancer stem-like cells are responsive to signals from ASCs. Paracrine factors secreted by locally-delivered ASCs may, therefore, contribute to the modulation of signaling pathways involved in cancer progression, metastasis, and drug resistance.     

Endothelial and cancer cells interact with mesenchymal stem cells via both microparticles and secreted factors

Tightly associated with blood vessels in their perivascular niche, human mesenchymal stem cells (MSCs) closely interact with endothelial cells (ECs). MSCs also home to tumours and interact with cancer cells (CCs). Microparticles (MPs) are cell‐derived vesicles released into the extracellular environment along with secreted factors. MPs are capable of intercellular signalling and, as biomolecular shuttles, transfer proteins and RNA from one cell to another. Here, we characterize interactions among ECs, CCs and MSCs via MPs and secreted factors in vitro. MPs and non‐MP secreted factors (Sup) were isolated from serum‐free medium conditioned by human microvascular ECs (HMEC‐1) or by the CC line HT1080. Fluorescently labelled MPs were prepared from cells treated with membrane dyes, and cytosolic GFP‐containing MPs were isolated from cells transduced with CMV‐GFP lentivirus. MSCs were treated with MPs, Sup, or vehicle controls, and analysed for MP uptake, proliferation, migration, activation of intracellular signalling pathways and cytokine release. Fluorescently labelled MPs fused with MSCs, transferring the fluorescent dyes to the MSC surface. GFP was transferred to and retained in MSCs incubated with GFP‐MPs, but not free GFP. Thus, only MP‐associated cellular proteins were taken up and retained by MSCs, suggesting that MP biomolecules, but not secreted factors, are shuttled to MSCs. MP and Sup treatment significantly increased MSC proliferation, migration, and MMP‐1, MMP‐3, CCL‐2/MCP‐1 and IL‐6 secretion compared with vehicle controls. MSCs treated with Sup and MPs also exhibited activated NF‐κB signalling. Taken together, these results suggest that MPs act to regulate MSC functions through several mechanisms.     

Exosomal miR-21-5p derived from bone marrow mesenchymal stem cells promote osteosarcoma cell proliferation and invasion by targeting PIK3R1

Mesenchymal stem cells (MSCs) are a class of pluripotent cells that can release a large number of exosomes which act as paracrine mediators in tumour-associated microenvironment. However, the role of MSC-derived exosomes in pathogenesis and progression of cancer cells especially osteosarcoma has not been thoroughly clarified until now. In this study, we established a co-culture model for human bone marrow-derived MSCs with osteosarcoma cells, then extraction of exosomes from induced MSCs and study the role of MSC-derived exosomes in the progression of osteosarcoma cell. The aim of this study was to address potential cell biological effects between MSCs and osteosarcoma cells. The results showed that MSC-derived exosomes can significantly promote osteosarcoma cells’ proliferation and invasion. We also found that miR-21-5p was significantly over-expressed in MSCs and MSC-derived exosomes by quantitative real-time polymerase chain reaction (qRT-PCR), compared with human foetal osteoblastic cells hFOB1.19. MSC-derived exosomes transfected with miR-21-5p could significantly enhance the proliferation and invasion of osteosarcoma cells in vitro and in vivo. Bioinformatics analysis and dual-luciferase reporter gene assays validated the targeted relationship between exosomal miR-21-5p and PIK3R1; we further demonstrated that miR-21-5p-abundant exosomes derived human bone marrow MSCs could activate PI3K/Akt/mTOR pathway by suppressing PIK3R1 expression in osteosarcoma cells. In summary, our study provides new insights into the interaction between human bone marrow MSCs and osteosarcoma cells in tumour-associated microenvironment.     

Production of CCL20 from lung cancer cells induces the cell migration and proliferation through PI3K pathway

Tumour inflammatory microenvironment is considered to play a role in the sensitivity of tumour cells to therapies and prognosis of patients with lung cancer. The expression of CCL20, one of the critical chemoattractants responsible for inflammation cells recruitment, has been shown overexpressed in variety of tumours. This study aimed at investigating potential mechanisms of CCL20 function and production in human non‐small cell lung cancer (NSCLC). Expression of CCL20 gene and protein in lung tissues of patients with NSCLC and NSCLC cells (A549) were determined. The interleukin (IL)‐1β‐induced signal pathways in A549 and the effect of CCL20‐induced A549 cell migration and proliferation were determined using migration assays and cell‐alive monitoring system. Mechanisms of signal pathways involved in the migration of CCL20 were also studied. We initially found that NSCLC tumour tissues markedly overexpressed CCL20 in comparison with normal lung samples. In addition, IL‐1β could directly promote CCL20 production in lung cancer cells, which was inhibited by extracellular signal‐regulated kinase (ERK)1/2 inhibitor, p38 mitogen‐activated protein kinase (p38 MARP) inhibitor or PI3K inhibitors. CCL20 promoted lung cancer cells migration and proliferation in an autocrine manner via activation of ERK1/2‐MAPK and PI3K pathways. Our data indicated that IL‐1β could stimulate CCL20 production from lung cancer cells through the activation of MAPKs and PI3K signal pathways, and the auto‐secretion of CCL20 could promote lung cancer cell migration and proliferation through the activation of ERK and PI3K signal pathways. Our results may provide a novel evidence that CCL20 could be a new therapeutic target for lung cancer.     

Insulin-like growth factor binding protein-2 mediates the inhibition of DNA synthesis by transforming growth factor-beta in mink lung epithelial cells.

Insulin-like growth factor binding protein-3 (IGFBP-3) has been proposed to mediate the growth inhibitory effects of transforming growth factor (TGF)-beta in breast and prostate cancer cells. Both TGF-beta and exogenous IGFBP-3 inhibit DNA synthesis in Mv1 mink lung epithelial cells (CCL64). The present study asks whether IGFBPs synthesized by CCL64 cells mediate growth inhibition by TGF-beta. CCL64 cells synthesize and secrete a single 34-kDa IGFBP that was identified as IGFBP-2 by immunoprecipitation and immunodepletion. Recombinant bovine IGFBP-2 inhibited CCL64 DNA synthesis in serum-free media in an IGF-independent manner. Coincubation with Leu(60)-IGF-I, an IGF-I analog that binds to IGFBPs with higher affinity than to IGF-I receptors, decreased the inhibition by bIGFBP-2. Leu(60)-IGF-I also decreased the inhibition of CCL64 DNA synthesis by TGF-beta by up to 70%, whereas Long-R3-IGF-I, an IGF-I analog with higher affinity for IGF-I receptors than for IGFBPs, did not decrease inhibition, suggesting that the effect of Leu(60)-IGF-I resulted from its forming complexes with endogenous IGFBPs. Leu(60)-IGF-I did not decrease TGF-beta stimulation of a Smad3-dependent reporter gene. Following incubation of intact CCL64 cells with bIGFBP-2 at 0 degrees C, bIGFBP-2 was recovered in membrane fractions; membrane association was abolished by coincubation with Leu(60)-IGF-I. If exogenous and secreted IGFBP-2 must bind to CCL64 cells to inhibit DNA synthesis, Leu(60)-IGF-I might reduce the inhibition of DNA synthesis by bIGFBP-2 or TGF-beta by inhibiting the association of IGFBP-2 in the media with CCL64 cells. Since TGF-beta does not increase IGFBP-2 abundance, we propose that TGF-beta sensitizes CCL64 cells to the latent growth inhibitory activity of endogenous IGFBP-2 by potentiating an intracellular IGFBP-2 signaling pathway or by promoting the association of secreted IGFBP-2 with the plasma membrane.     

Modulation of eotaxin-3 (CCL26) in alveolar type II epithelial cells

Airway epithelial inflammation associated with emphysema, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and asthma is regulated in part by alveolar type II cell chemokine signaling. Data suggest that resident lung cells use CCR3, CCR5 and CCR2 chemokine receptor/ligand systems to regulate the profile of leukocytes recruited in disease-associated inflammatory conditions. Thus studies were designed to test whether alveolar type II cells possess a Th1-activated CCR5-ligand system that modulates the Th2-activated CCR3/eotaxin-2 (CCL24), eotaxin-3 (CCL26) chemokine systems. The A549 alveolar type II epithelial-like cell culture model was used to demonstrate that alveolar type II cells constitutively express CCR5 which may be upregulated by MIP-1alpha (CCL3) whose expression was induced by the Th1 cytokines IL-1beta and IFN-gamma. Selective down-regulation of CCL26, but not CCL24, was observed in CCL3 and IL-4/CCL3 stimulated cells. Down-regulation was reversed by anti-CCR5 neutralizing antibody treatment. Thus, one mechanism through which Th1-activated CCCR5/ligand pathways modulate Th2-activated CCR3/ligand pathways is the differential down-regulation of CCL26 expression. Results suggest that the CCR3 and CCR5 receptor/ligand signaling pathways may be important targets for development of novel mechanism-based adjunctive therapies designed to abrogate the chronic inflammation associated with airway diseases.     

Hedgehog-mediated paracrine interaction between hepatic stellate cells and marrow-derived mesenchymal stem cells

During liver injury, bone marrow-derived mesenchymal stem cells (MSCs) can migrate and differentiate into hepatocytes. Hepatic stellate cell (SC) activation is a pivotal event in the development of liver fibrosis. Therefore, we hypothesized that SCs may play an important role in regulating MSC proliferation and differentiation through the paracrine signaling pathway. We demonstrate that MSCs and SCs both express hedgehog (Hh) pathway components, including its ligands, receptors, and target genes. Transwell co-cultures of SCs and MSCs showed that the SCs produced sonic hedgehog (Shh), which enhanced the proliferation and differentiation of MSCs. These findings demonstrate that SCs indirectly modulate the activity of MSCs in vitro via the Hh pathway, and provide a plausible explanation for the mechanisms of transplanted MSCs in the treatment of liver fibrosis.     

miR‐155‐5p inhibition rejuvenates aged mesenchymal stem cells and enhances cardioprotection following infarction

Aging impairs the functions of human mesenchymal stem cells (MSCs), thereby severely reducing their beneficial effects on myocardial infarction (MI). MicroRNAs (miRNAs) play crucial roles in regulating the senescence of MSCs; however, the underlying mechanisms remain unclear. Here, we investigated the significance of miR‐155‐5p in regulating MSC senescence and whether inhibition of miR‐155‐5p could rejuvenate aged MSCs (AMSCs) to enhance their therapeutic efficacy for MI. Young MSCs (YMSCs) and AMSCs were isolated from young and aged donors, respectively. The cellular senescence of MSCs was evaluated by senescence‐associated β‐galactosidase (SA‐β‐gal) staining. Compared with YMSCs, AMSCs exhibited increased cellular senescence as evidenced by increased SA‐β‐gal activity and decreased proliferative capacity and paracrine effects. The expression of miR‐155‐5p was much higher in both serum and MSCs from aged donors than young donors. Upregulation of miR‐155‐5p in YMSCs led to increased cellular senescence, whereas downregulation of miR‐155‐5p decreased AMSC senescence. Mechanistically, miR‐155‐5p inhibited mitochondrial fission and increased mitochondrial fusion in MSCs via the AMPK signaling pathway, thereby resulting in cellular senescence by repressing the expression of Cab39. These effects were partially reversed by treatment with AMPK activator or mitofusin2‐specific siRNA (Mfn2‐siRNA). By enhancing angiogenesis and promoting cell survival, transplantation of anti‐miR‐155‐5p‐AMSCs led to improved cardiac function in an aged mouse model of MI compared with transplantation of AMSCs. In summary, our study shows that miR‐155‐5p mediates MSC senescence by regulating the Cab39/AMPK signaling pathway and miR‐155‐5p is a novel target to rejuvenate AMSCs and enhance their cardioprotective effects.     

CCL5 secreted by senescent theca-interstitial cells inhibits preantral follicular development via granulosa cellular apoptosis

As a fundamental aging mechanism, cellular senescence causes chronic inflammation via the senescence-associated secretory phenotype (SASP). Theca-interstitial cells are an essential but little-studied component of follicle development in the ovarian microenvironment. In the present study, we observed significant cellular senescence in theca-interstitial cells and secretion of chemokine (C-C motif) ligand 5 (CCL5) by these cells during aging. Furthermore, we aimed to investigate whether and how senescence-associated secretory phenotype (SASP)-associated CCL5 may be involved in follicle development. Increased levels of CCL5 in the microenvironment of follicles attenuated preantral follicle growth, survival, and estradiol secretion. Oocyte maturation and the expression of zona pellucida 3 and differentiation factor 9 (GDF9) were also inhibited by CCL5. Granulosa cell apoptosis in follicles was promoted by CCL5, accompanied by the phosphorylation of nuclear factor-κB by CCL5 and inhibition of the PI3K/AKT pathway. These results suggest that SASP-associated CCL5 produced by senescent theca-interstitial cells may impair follicle development and maturation during ovarian aging by promoting granulosa cell apoptosis.     

Cardiomyocyte-like cells differentiation from non β-catenin expression mesenchymal stem cells

Recent studies have shown that block wnt/β-catenin signaling pathway is integrant for cardiomyocytes differentiation from bone marrow mesenchymal stem cells (MSCs). By transducing the MSCs with lentivirus which contain β-catenin interference RNA, we screened out the non β-catenin expression clone. In the establishment of knockdown β-catenin in MSCs, we investigated the role of 5-azacytidine (5-aza), salvianolic acid B (salB), and cardiomyocytes lysis medium (CLM) in inducing MSCs to differentiate into cardiomyocyte-like cells. A method for culturing MSCs and cardiomyocytes was established. Purified MSCs were investigated by flow cytometry. The MSCs were positive for CD90 and CD29, but negative for CD34 and CD45. Meanwhile, the cardiomyocytes contracted spontaneously after 24 h of seeding into the plates. The fourth-passage non-β-catenin expression MSCs were divided into eight groups: control group, 5-aza, salB, CLM, 5-aza + salB, 5-aza + CLM, salB + CLM, and 5-aza + salB + CLM. The gene and protein expression of cTnT, α-actin, β-myosin, β-catenin, and GSK-3β were detected by quantitative real-time PCR and Western blotting. Our results showed that cTnT expression in 5-aza + salB + CLM group was ninefold higher than in the control group in the non-β-catenin MSCs model, implying that cardiomyocytes differentiation from MSCs is an extremely complicated process and it is necessary to consider the internal and external environmental conditions, such as suitable pharmaceutical inducers, cardiomyocytes microenvironments, inhibition of the negative signaling pathway and so on.